~\'1(4~ - World Radio History

$: ~\'1(4~ - World Radio History$
~9/ A JOURNAL FOR

Rt\DIID EXPERIMENTERS v.~~~~~~~=========

Vol. 14 No. 5 NOVEMBER 1938 (Copyright) Price I /6

HOW TO USE THE CATHODE RAY TUBE A 'IB·P•&• Book by J. H. REYNER. B.Sc., D.l.C .. A M.l.E.E. A practical treatise of great value to ex· pcrimenters and servicemen. Numerous illustrat ions.

Price 1 /- Post Free

Ob:oinoble (ram-

~\'1(4~ THE SCIENTIFIC

VALVE BRITISH MADE

CATHODE RAY TUBES TYPE CR3

3" Screen 7-pin base Green Screen

fl-l-0

TYPE CR3A 3" Screen 9-pin base Blue Screen

fl-7-6

HIVAC VALVES FOR CATHODE RA Y EQUIPM ENT GRI GR2 Grid controlled rec- IO/ Grid controlled rec-tifier, mercury filled - tificr, Argon filled 10 /•

HVUI High voltage half wave rectifier delivering up to 6,000 j volts, at 3 milliamperes IS 6

Complece technical details of the above and of che full range of Hivac bauery and mains valves will be sent on requesc.

THE HIGH VACUUM VALVE CO., LTD., 111-117 FARRINGDON RD., LONDON, E.C.1

---ii. THE T. & !?. IJULI.f;J'J N, :'\ovcmlwr 193~.

CRITICAL TESTING

AU • • Avo " lnsttumtnU may be purchased on

Dtforrtd T •rms.

/i:~U'f:>tJ••ftu' '"'OU' RL&i>lnt.I Tr 1.lr .11"rl·

demands the

AVOMINOR (ll•1d. Trade Mark ,)

Electrical Me<l.surinc Ins trument ~~~The ~~~~~~~~.

In c ' 'it , r...•ith lu;:/; \fll/ IJ.:&' fo1d'l 1 fottr • tls1-1 ,.g~abl< lti: ft1i..l~ HtJ tna.. .It/, cltr\ and uuJr ~

'"'" br"'lt:f1.

£3: IOs.

HIGH RES ISTANCE

AVOMINOR Electrical T estinc Instrument

An extremely senstt ive 10 r~ngc O.C. moving-coil microammeter also alibr;ued as a multi- f'2ngc voltmeter ind me1ohmmeu1r. lu she volt.ace: ranies are all at 10 ,OOO oh m s per volt, the consumption at lull sQle deflection being 50 microamps. Th1l extreme seniitivity permits precision readings with nccllslbl• lo.d ing and is em inently suitable for me.uuring grid, screen and anode vola,e.s. and also for television. On the lower of its two current nni es . .a deflection of app,.-ox. I mm. It produced by a curnmt of one micro ... amp .• allowini accunte re-Jd· 1ns:s of grid current, etc.

U niversal AVOM INOR Electrical Mea1urinr fnnrumonc

A precis1on meter (or measurln1 A.C. J.nd O.C. volt" O .C. mllllamps., and ohms. le has 22 r;inges . An 11ccuratc movln1·co1I movement gives a l·ln. full·sc.alc dertoctlon. Total resistance Is 200,000 ohnu. Complete wlth leads, lnttrchanioable testlnc prods and crocodll• dlp1 : and Inn rue- £5 . I Os tlon booklet . . ... ... • •

The D.C. AVOMINOR '··•~;,'. ... ~. Electrical Moa1 urine Instrument

13 Instruments In one. Tests circulu, valve1, com ponents, batteries Gnd power units. In case. with luds. lnterchanieable crocodile clips and tesclni prods 1nd lnnruction booklet. ~/Write (or fully ducriptiue pamphlets Sole Proprierors o"'1 Manufacrurors : THE AUTOMATIC COI L WINDER & ELECTRICAL EQUIPMENT CO., LTD., W inder House, Oou,lu Screec, London,S.W.I

Telephone : Victoria 3<404.7.

For Sho1·tand Ultra S/W Work

OM' t for r •I to und for a <Ol>r o( our lat~ll

Catolorue " T.lt"

In the rece ntly published Catalogue ofCLIX Components, amateurs and experimente rs will find an excellen t range of Frequenlite (Ceramic) com ponents for use in Television work and in all lowloss high efficiency circuits. Send for a copy now and please mention the "T. & R. Bulletin. " CLIX TRIMMER CONDENSERS. Here is another compon en t in which the use of "Frequentitc" Ceramic is unr ivalled. The unique design of vane permits the condenser to be suspended in the wiring without risk of disturbance through strain being thrown on the con necting leads.

Type Price Tc I MIDGET 3-30 mfds. 6 d. each. Tc 2 4-50 mfds. 6 d. Tc 3 DOUBLE 3-30 mfds. 116

C LI X " ACORN " VALVE HOLDERS. In addition to their low-loss characteristics occasioned by the Frequentite bases, the method of contacting the valve pins with Nickel Silve r clip sockets makes for knife-edge binding.

English 90 degrees, American 60 degrees 2 '- each.

r=n n~ BRITISH M ECHANICAL PRODUCTIONS LIMITED 7go ROCHESTER ROW l,:::I &.::I U ~ LONDON S .W. l

Tiii:' I. <So U. /ICJ.l. l:'J IS, :'\o , ·ember 1938. iii

GSNl'5

JOHNSON "Q" BEAM ANTENNA FOR 2 BAND OPERATION The new Johnson " Q " Beam Antenna requires an extra Johnson "Q " only. If you have a 20-metre " Q." using another 20-metre " Q " will increase your signal strength 'I DB. on 20 metres and 6 DB. on 10 metres. t he one Antenna serving for both bands. Similarly, if you have a 10-metre "Q," another 10-metre " Q " will give the same conditions on 10 and 5. We give Johnson 's full instruc· tions for the " Q " Beam with every Johnson " Q " sold.

Prices:

JOHNSON '' Q" 20 Mett·es, 39 /6

JOHNSON "Q" 10 Metr es, 26 /6

WATCH for our announcement next issue. A 25~WATT CW. KIT for operation on 20, '10, 80 or 160 metres. complete with 230-volt power supply, Raytheon tubes, Bliley crystal. latest type square meter, assembled, only requires wiring £4 / 19 /6

Can be wired by any ham in three hours with instructions provided.

RCO Oscilloscope The response to our advertisement on the above was so great as to completely disorganise our delivery. We must apologise to those who ordered and who did not get delivery in less than 14 days. We now can, however, give you immediate delivery, and if you have already seen one of these in action, you will realize the exceptional value offered. The RCO will give you a complete picture of operating conditions in your Transmitter, in addition, telling you the percentage modulation on incoming signals. It is complete with 3-in. " Hivac " Cathode Ray Tube, self-contained power supply for 200/230-volt operation. I ,OOO volts is available to operate the tube at full sensitivity. Horizontal and vertical plates a re brought o ut to t he side of the Cabinet, and a self-contained 50-cycle sweep Is provided. The Cabinet matches exactly, and is the same height as HRO. RME. 69 and Hall icrafter Receivers. Price, with a ll Tubes, ready for operation ... £4 19s. 6d . A charge of 10s. is made for the Tube Container to ensure safe arrival of the Cathode Ray Tube. This amount is refundable in full , subject to the case being returned to our premises with in fou r days of receipt.

STOCKTAKING BARGAINS AT THIS TIME OF THE YEAR WF. HAVE A NUMBER OF ODDMENTS WE HAVE

DECIDED TO CL.EAR. IN ORDER TO MAKE MORE ROOM FOR INCOMING STOCKS.

THESE OFFERS CANNOT RCA. 913 Cathod• Ray Tube and 855 ias·filltd tricier tube for ume. list

BE REPEA TED. H URRY I 54 /-. th• pair ... ... • .. 37 6

RME. 69. Stock-so1l•d demonstration model. only used in our Showrooms . On• only 30 cns.

McMURDO MASTERPIECE Ill , 12 tubes. Hich Fidelity Audio ( ll watts), Speaker Air-tuned IFS. sepinte Beat Oscillator. Eltetncal B•nd Sprud, cost over £60 : one only. Complete w ith High Fid•lity Sp•aker ... £15

NATIONAL SW45, same as SW), but 2 extra audio sta&es. complete wich tubes. C•ll•rt only, come and ~lck yours ... ... ... ... SO /·

TOBE, Amueur Communituion Receiver, 7 valves, with 180 deis. bJnd spread on 2moueur bands, beu oscilb.· tor, a.v.c. Complete Jn Cabinet. Stock· soiled only. List £17 17s. 6d. ONE ONLY .. . ... £12 17s. 6d .

McMURDO 100-watt. 'Phone Tnns · mitter (uses RK20). con £15. lets tub., and Xal. Ono only ... ... 17 ans.

UTAH 80-watt 6L6 Tronsm•tter. luut CW type. with tub., and Xtal (230 v.)

£17 G.T.C . 25-watt 6l6 CW. Tnn>mlttor kit,

complete- with tube,, meter mnd Xtal ... ... £7

GROSS CP60- IOO-watt Transmitter ChaUts. uses 47, 53 •nd 35 T. less tubes •nd x .. 1. but with coils for 20 and 40 metres ... ... £5 IOs. Od.

GROSS CPSS- 100-watt Tr•nsmottcr Ch.,sis. uses 42. 6l6, 2-T. lO's coil1 for 10 and 20 motr•s. no tub ... £5 101.

GROSS CWlS- SO.w;att Transmitter Cha.ssis, uses 17. 46. 2·46s, coils for 20, 40,80and 160metr•s(notubcs), £5 101. All rhe above transmitters ore brand new

and unused. TAYLOR T.1 25. List £4 ISs . ... £3 TAYLOR T.ISS. List £6 ... ... £4

AMPEREX. HF.200. list £8. £517s.6d. AMPEREX. 21 IG . List 0 10..,

£2 19s. 6d. AMPEREX. 841 carbon anod•. list

£2 ... ... ... ... ... 17 /6 WESTERN ELECTRIC 211E .. . IS/ · HOYT l.attst square: m111iameten.

Type S93 ... ... ... ... 7 /3 DITTO, but mov1n1 coil. Typ• S91, 22 /6 HOYT 31-in. R. F. Antenna amm•tors.

I. I, 1 l. 3 amps with ztro adjust ors, 17 /6 GENUINE CRYSTAL MIKES (Brush

Crysul Unot), whlle they l•st. new. 19 /6 Chromium Sund for nm• ... ... 6 /6 AMER ICA N Smooth in1 Chokes,

lnterluv•d and shrouded 20 hy . ISO m /A. 3SO ohms. .. . ... 4 / 11

AMERICAN Smoothine Chokes, 1nterluved and shroud•d 20 hy 100 m /A. SOO ohms . ... .. . 4 / 11

AMERICAN Smoothing Chokes. Interleaved but not shrouded. 100 m /A SOO ohms ... ... l / 11

AMERICAN Smoothinr C hokes, lnt•rl .. v•d but not shrouded. IS hy. ISO ohms. .. ... 3 / 11

AMERICAN Smoothlnr Chokes, interluved but not shrouded . IS hy. 200 rn / A. 200 ohms. ... ... 8 /6

JOHNS ON TYPE 21 1 SO.watt. Cera-mic Sockeu ... 4 /9

SPECIAL ! ! ! 01l·r.llod Condensers by ludln& m•k•r. with reversible fhdni-i.e., Chaun with connections underneath or ba.uboud connections above. 4 MF I ,OOO v. workln& (3.000 v,. O.C.

tut) ... ... ... . .. 6 / 11 2 MF 2,000 v. work1n1 (6.000 v •• D.C .

test) ... ... ... 9 / 11 RAYMART MANUAL

70 Paies o( pr.aictical information written by GSNI, G2AK and G8HO. In lan&uagc you can undersund. 7 l d .. Post Free .

RADIOMART THE SHORT-WAVE SPECIA LISTS. W e are a uthorised Distributors fo r BLILEY, THORDARSON , TAYLOR TUBES, RME, BASSETT CONCENTRIC CABLE, HOYT METERS,

COLLINS, NATIONAL, ETC, Send us your enquirJcs. Lare• scotks arried.

GS NI (BIRMINGHAM) LT D. 44 HOLLOWAY HEAD, BIRMINGHAM , I Telephone : MIDLAND 1154

--

j , .

ONCE AGAIN

n:t A.C.S. RAD IO

~~ offer , in addition to the regularly advertised types of New Communication Receivers. a selection of shop-soiled and reconditioned bargains. We have been busy in our workshops checking and re-aligning these sets, and can guarantee their performance equal to new. Another point worth considering is that all sets, new or second-hand, carry our 3 months' guarantee, and we wi ll willingly correct any trouble. however slight, that may occur during this period.

THIS M O NTH 'S BA RGA IN LIST

R ME 69, Standard Model. perfect condition £30 0 O

H allicraft er's Sky C hallenger I £15 0 0 H al licrafter 's U ltr a Skyrider,

3.5 to 55 metres, complete with large speaker and crystal £ 18 18 0

Hal lic rafter's Super S kyrider S-5, 10 to 160 metres... £8 8 O

National NC-100, complete with speaker in cabinet £25 10 0

National NC-10 1 X, Ham-Band, complete with speaker 07 0 0

T o be Deutsch man n H am-Band, complete with speaker £12 12 0

Eddystonc Ever est 5-Met re Tra nscei ver, complete £6 10 0

Simpla t V.G. Recording Am· plifie r , cost £25, as new £12 10 0

Pe rmarec S uper C a rbon Mic r o· phone, on table stand £2 I 5 0

Epoch Moving Coil Micro· phone, on floor stand, corn· plcte with special matching transformer £2 12 6

C ossor N eon Indica tor Tubes, FB for RF 1 /6 each

NEW C OMPONENT S

A.C.S. Special C r ysta l Microphones, fitted with Brush inserts , 39 /6. Kenco Bug Keys, 21 /·. Signal Keys K63, 17 /6. Tube S hields, 3-piecc, I /· each. Beede Panel Meters, 2! ins., 18 / ·. l.C .A. Acorn Sockets, 3 /· each. 1.C.A. Plug·in C o il Fo r ms, 3! in. by 2 ~ in .. 4 /6. TUBES: RKI I, RKl2. 17 /6. Taylor T20, TZ20. 17 ,16. HO. TZ40, 24 /· .

---·-

Till:: /' l- H. Hf" l .11: f'l .Y, :->m·cmbcr 193$.

iPOJ.All .,_..........._j.~?& AND NS.F.

COMPONENTS TYPE • E ' Short-Wave

CONDENSERS Cerimic bas~. Soldered

•F•l'l'P-- brau vanes. For base.Nt..'1111~.J board or panel mounting.

AI R D IELECTRI C

TRI MME R I

Cenmlc bue, 1oldertd brau v1ne:s. Sp•c1ally dttl&ntd to m11na ln accuracy or Htunc. Made 1n ap~cltles. :

25 14 F. ) so .. l 75 .. J

100 ..

Pr ice

4/-

PR ICES: Smile .00016 ... S /· TwoGoni2x.00016 1016

SPECIFICATION OF A .C. RECEIVER

POLAR 28/56 Mc. I Air OleleCtric - Tnm~er

C.901 25 mmf, I S,W . Type "E" Slnile

. 00016. Volume Control V / I S,000 ohm., Volume Control V /1 SO.OOO ohms. Volume Control V /'4 SOO.OOO ohm•.

l Reshton I-watt ISO ohms. I do. I ,OOO ohms. 2 do. S,000 ohms.

Resistor I-watt J.me,. do. 25.000 ohms . do, 10,000 ohms . do, 100 ohms.

Mi cro Horizontal Drive. fl ttt'd decr·ee scale.

I uc_h Tubular Condensers. .02 and .01 .

I uch Electroly<1a, 1, 6 and 8 mid.

l Runtors 2-watt 20,000 ohms.

WINGROVE & ROGERS ud. 12 Da r t mo ut h St., Lo ndon, S.W.1

Phone · Abbey lln 3

Works : Old Swan, Liverpool

m 6 164

THE. T. ci;, R . BUlLETl \' ' ' :Ko,·ember 1938. \ ' ,

i'~~~ia-rowa Type "A ,, H eadphones

SEVEN IMPORTANT POINTS

TYPE " A"

50/-

The acknowledged su . . Type "A" H d h perromy ofS. G. Brown ea p ones with d ' bi

reed is accou n ced for b h a JU Sea e their design and const Y. t e excellence of ruction .

I. SENS ITIVITY (Frequenc response approx. 25-1 6,oob c.p.s.

2. ADJUSTM ENT (Reed Setting maintained).

3· QUALITY (Absence or resonance).

6. MOVEM ENT (Dust and damp proof).

7. COM FORT (Light in weight with perfect head band adjustment) .

per pair 4. RESISTANCE(2,000 ohms Suppl' d each earpiece). Used. by H.M. Royal Navy

ie wo_und to special res1'st- B I h on h 5. INSULATION (Head- r us and Foreign A' S ' ces Wit out extra charge. b d vices Th B B c " er-. an s and cases efficiently • . e · · .. etc. : and

S

insulated from wiring) b~ rad io amateurs throughout

. G. BROWN LTD., VICTORIA . t e world. ROAD, ACT. ON, W.3. TI AC e .: Orn ll 74

THE QUICKEST, EASIEST ROAD

CODE SKILL to

T. R. McELROY, World 's Offi cial Code Cha mpion, 51YS:

-CAN OLER TRAINING! There's no roynl road 10 lenmln~-but the r e IS n quick. s ure wnr, to jlcnulne COOE s klU. Thousands upon thou~nnds or Cundler Trn ncd Operators have proved the volue of this trul)' r emnrknble system ol Code Ins truction, lncludlnll. champions and mnny of the fastest o{)(!rntors In t h e world. Candle r teaches you the co rrect (und nrn cn1o ts , proper mcnt nJ and phys ical coordlnnllo n - nnd, In n corn pa rntlvely s hort time, you will find yo u rt1clC rcadln~ words, yes, c, ... e.n sentences . without s tniln or conscious effort- as easily ns you re"d print. Your proll,rus, a fte r months of un11roductlve, undirected proctJce. is al most uncnnn)'-Jt costs you only postage to lcnm about Cnndler Trainln!!.· Pos t the cnupon today for the new edition of Candler's Book of Facts. It's FR EE upon r equest .

"The C=dl<r Systcin tauiiht inc to rc3d code b>' sound :as ou1h• 3S I read print, :>Dd to put It dOwn on my t\1.ewrit<r b,· touch . ...;1bout ha,~ni; to ttunk ho" .. 'Ol'ds arc spclltd. Candler teacM \'O\I automatic sound consc10\l!Jlt'-;, conttntntion and coonhnation-absOlutc essentials to the hand:lllS of fast code. And the surpri>in; pan is tha 1 you :u:qwre these osscntials 50ctfor1JC$'1\' that \'OU will be ;imazcd at your own p~ • E\-ery day makes you a bell er operator once '""' ba~e teamed the Candler pnnciplc." •

POST COUPON TODAY FOR FREE BOOK OF FACTS To: H. Freeman, 121 Kingsu1ay, London, W.C.2 (R oom SS) l..ondon Reprcscn<at iv• fot Candl•r System Co .. As/rl1llc. N. Carol1t10, U.S.A.

Please send me FREE BOOK O F FACTS.

NAME . . ..... .... .................. .................................................................. .

2

vi.

The

Wireless World

SPECIAL

VALVE DATA NUMBER dated Nov. IOth

Includes a supplement with data relating to over I ,OOO British and American receiving valves, tabulated for easy reference, with base connections. Other features deal with valve input resistance on ul tra·short waves, and a comparison between the new German steel valves and glass types and also their earlier American metal prototypes.

From all Newsugents 1111tl Dookst11ll~. 4d.

ILIFFEf& S ONS LTD. Dorset H ouse, Stamford St., London, S.E.I

TJJE T. & R. 8ULLE1'1N, ~ovcmber 1938.

YOU Includes a special chapter

on Television as wel I as

up-to-date informat ion on

all rectification problems.

_______ co UPON ____ __ .....,

WESTINGHOUSE BRAKE & SIGNAL CO. LTD., 82, York Way, King's Cross, London, N.1.

I enclose 3d. in stamps. Please send me "The All-Metal Way, 1939."

Nome ................................ . ....................... . ....... ..

Address ................................................... . .......... . T.R.B. 11 / 38.

===EVRIZONE=== 12-VALVE

COMMUNICATION RECEIVER

Incorporat ing the Supe r · Tuner Unit (Tliu Unit i1 0/10 aoai/al>k -rattfJL. Pnc:e £4-10-0)

A1 WS>Plied to tk B.JJ.C. Waveranges from 5-190 m etres continuous PRICE £45 (Loucfs-ur extra.)

In tMir i~ of Od. Z7th, f>Oldutn< and -1ihl iuJ,eJ .., a hiJlt-1rack t><Tmt:nml mazn<TV< of oolume than i• PoUible " '"' in tk bat • all·wa<'e • ..is."

The unbiased rest repor't or" The W irele:u W orld 0

will convince you of the remarkable qu;i.Hty and cap;ibilitie-sof thi s se"t., which, in their own words, has "such an excellent pe rformance:• If after referrln1 to the r eport you r~uire further inform~tion, we shall be 1lad to s upply it.-(Reprint of R eport •ent post free on request).

EVRIZONE RADIO & TELEVISION CO. L TO. 2, Southlands Road, Bromley, Kent.

:=:=:=:::::;: ' Phone: Ravensbour,nc 1957

THE T. ~<:.. R /Jl'l.l.ETI.\', .'.'o, ·embcr 19:l:-..

I : ' I ' . FROM YOUR RAD IO DEALER; W . H. SMITH & SON, or in difficulty send I /2 to STRATTON & Co., Ltd. Eddystonc Works,

Bromsgrove Street, Birmingham. London Service: Webb's Radio, 14, Soho Street, W.I.

vii

y j jj THE T. C.. R. Bl'I l.ETIN. :\o\'cmber 1938.

THE INCORPORATED

RADIO SOCIETY OF GREAT BRITAIN 53, VICTORIA STREET ,

LONDON, S.W.1.

VOL. 14. No. 5.

T HE T. & R. Bulletin is published on

or about the I Sth day in each

month, and a copy is despatched free

of charge to each member. Changes of address should be communicated

promptly to the Headquarters of the Society.

T HE Secretary-Editor will be pleased

to consider for publ ication, articles

of technical or general interest. Intend·

Ing contributors arc requested to indicate

in advance the scope to be covered by the utlcle under consideration.

COUNCIL 1938. PRESIDENT:

A. E. Watts (G6UN)

EXECUTIVE VICE-PRESIDENT :

A. D. Gay (G6NF)

HONORARY TREASURER:

A. 0. Milne (G2MI}

IMM EDIATE PAST PRESIDENT :

E. D. Ostermeyer (GSAR)

HONORARY EDITOR :

H. Bevan Swift (G2TI)

MEMBERS: Viscount Carlow (G6XX) H. A. M. Clark (G60T)

F. Charman (G6CJ) J. W. Mathews (G6LL)

J. D. Chisholm (G2CX) H. C. Page (G6PA)

H. A. M. Whyte (G6WY)

SECRETARY-EDITOR :

John Clarricoats (G6CL)

H ONORARY M EMBERS: Si r Oliver Lodie. O.Sc .. Ll.O .. F.R.S.

E. Diwson Ostermoycr, Esq.

PAST PRESIDENTS : The late A. A. Campbell Swinton, E1q.

(1913-20). The late MaiorJ. Erskine Murray (1921). The lat,c Admiral Sir Henry B. Jackson

( 1922). Profcuor W. H. Ecclet. O.Sc .. F.R.S .•

l".1.E.E. (1923·'4). Sir Oliver Lodge, D.Sc .. LL.O., F.R.S.

(192S).

The 1 .. e Brl1.-General Sir Capel Holden (1926·7).

Sir l>n Fmor. C.B.E. (i928). Gerald Ma reuse, Esq. ( 1929-30).

H. Bev•n Swift, Esq.,A.M.l.E.E. ( 1931·3). Arthur E. Wam, Esq. (193-4-6).

E. D•wson 011crmoyer, E>q. (i937).

VICE.PRES IDENTS :

M•urlce Child, Etq . Leslie MtMlchael, M.l.E.E .. F.lrut.R.E.

ALL I Colonel M. J. Dennis, C.B. Captain G. C. Price, T.D.

matters re ating to Advertising P. P. Eckersley. Esq .. M.l.E.E. should be addressed to Parrs Commander R. J. B. Hipplsley. O.B.E. J. H. Reevu. E1q .. M.A .• M.B.E.

Ad . . L d C Rene H. Klein, Etq .• F.R.S.A., M.l.R.E. E. J. Simmonds. Esq. vcrt1s1ng t ., raven House, 121, I Commander F. G. Lorin&. R.N ..

Kingsway, London, W.C.2. M.1.E.E. John Wyllie, Esq. HONORARY VICE-PRESI DENTS:

Sir Ambrotc Flemln1. M.A. E. H. Rayner. Etq .. O.Sc. G . F. Gre1ory, Etq .. M.l.M.E. E. H. Shau1hntuy, Esq., M.l.E.E.

THE T. & R. B'ULLETIN OFFICIAL JOURNAL

t DEVOTED TO THE

OF THE SCIENCE RADIO SOCIETY AND ADVANCEMENT OF GREAT BRITAIN OF AMATEUR RADIO

Hon. Editor: H. BEVAN SWIFT. General Editor: JOHN CLARRJCO./l.TS

Vol. XIV. No. 5.

Edltorl ul .. O ptimum l'llllc Tnnk Vn lucs A Useful Three-Circ ui t Osc ll-

lotor . . . . . . . . A 56128 Mc. A.C. 'l'.ll . I".

Rccch•c r .. Workshop l'rocUee A 56 .\l e. Driver Ponel Automnllc Chon{\e-over Sys-

tem for 100 per Cent . (lrcnk-ln Operntl on

Tltc 1938 "C.W. 56 Mc. Trophy •• Contest

Advertising Manager: HORACE FREEMAN

f'n!le 255 257

26 1 269 27 1

273

274

CONTENTS Cont emporary Lltcro ture ..

T h e llclpln~ H and .•

Exp erimental Secll on Cosmic Notes ..

The >l lonth on th e Ai r

The l8 .\l e . Band ..

The 56 .\IC. Band •.

The 8.£.R.U. Contests , 1939 The ll.A.F. CiviUan Wi reless

n cser\'e

P nj.\e 277 281

285 286 287 289 290

292

293

NOVEMBER 1938

lleudqunrt crs Colllnit

New l\tcn1bcrs 11,0.c. Not es .. Cor resp ondence

P ag.e 2'14

2')7

297 . . 298

Notes ond New8 from the llrltls h Is les 302

Fortheomlnll Even ts 30.i

1'hc West nt West on .. 3 12 Orllls h Not es nn cl News . . 3 13

Q.n.A . Section 3 15

THE STATUS OF THE TRANSMITTING AMATEUR

W E. and possibly many or our readers, read wilh much interest the editorial comments which were published recently in The Wireless World, wherein a pica was made that the Post Oflicc should relax their official attitude towards those who wish to become

transmitling amateurs. Emphasis was placed on the im portance to the country of ha,·ing :wailable, in case of

emergency, a large body of skilled wirelc~ operators, and the suggestion was pm forward that the Post Office should remo,·e e\·ery possible obstacle with a view to encouraging ownership of amateur transmitting stations.

We have loo much regard for those responsible ror the editorial policy of The Wireless ll'orld to cross swords wilh them on a matter which is of national im portance, but we believe our members will agree that unless the H1;tish Government arc prepared to open up additional frequency channels for training purposes, it would be unwise to permit our already overcrowded bands to be lilied with hundreds- perhaps thousands-of transmissions from persons who have no experim1'11fal interest in radio.

For lhc benefit of a ll concerned we would emphasise t hat within the last five years t he number of British I sles licence holders has increased from 1,300 to over 2,600. On 7 J\llc. a lone there arc approximately 1,200 British stations regularly active. With a band of frequencies less than 300 kilocycles wide available, the congestion has to be experienced to be fully appreciated. The Cairo Conrerence, held in February last, decided still rurthcr to reduce our operating space a round 7 Mc. by authorising broadcasting stations lo use the channel 7 ,200-7 ,300 kc.

\\"here, then, would the thousands of newcomers find room to be trained? \\'ith additional Ser\"ice demands it is unlikely that the G.P.O. would allow a laq~c increase of activity to take place on 1.7 or 3.5 )le. Possibly 1-1 ~le. would pro,·c an attraction, but that band is alre_ad.Y ,·ery overcrowded, due to the enormous amount or telephony operation, and the fact that it 1s clh·ided into three distinct sections as a result of the JOO kc. American telephony band having been placed in the centre.

The 2 ~le. band is too much like the parson's egg to be considered a training ground, whilst :;G )le. would, if the suggestion were adopted, dc\'elop, as it nearly dc\'clopccl a year or

256 Tll£ T. G- R. BULi, £'1 f.\", ~o\•cmbcr 1938.

so ago, inlo a band used for domestic back-chat. \\"c admit frankly there appears lilUe or no room available for tho~e who desire to become proficient wircle.<:s operators without indicating the line of experiment 1hcy wish to conduct.

Our considered opinion is that the amateur band:. -,hould continul' to be used hy tho:.c who can show sound technical reasons for requiring to use chem. For all others who ar(' anxious to become trnined operators, a~ remo,·cd from trained experimenters, we most heartily recommend thal they enrol either in the Royal ;\am! \\"ireless Auxiliary Reserve, or in the Ci,·ilian \\"ircless Reserve of the J~oyal .\ir Force.

* * * * THE A MATEUR RADIO HANDBOOK

Within a few days members will h:l\"e a\·ailable the first edit ion of our new / l 1m1/mr Radio Handbook. The publication of this all-British text-book brings to fruition an idea l which has been in the minds of many of us since earlv editions of A Guide lo . I 111ale11r Radio made their appearance.

We have not the slightest doubt that the Handbook will recei\'C tltl' :.upporl of a ll members, but in passing we would direct their altention to the fact that its produc tion has only been made possible Lhrough lhc splendid co-operation of a dozen or so 11H.:mbcrs who have given o[ their best over a period of many months.

The high lcchnicn l level which has been reached, coupled with the fact thal the book is profusely illustrated by about 250 clear diagrams, should ensure its popula1ity in official circles, as well as in " ham " shacks at home and abroad.

Production costs arc considerable, but if every member purchases one copy, and al lhc same time introd uces it to a friend, we need have no fears that the Handbook will pro,·c a financia l burden on the Society.

We arc convinced tha t 110 better value can be offered. Order your copy to-day and prove the truth of our contention.

• * * HONORARIUMS

In another page appears a list of members who have been awarded honorariums in recognition of the technical articles contributed bv them to the last rnlume of this j ournal.

These monetary awards a re not intended by- the Council to be regarded as payment for contributions, but as a lo ken of the Society's appreciation towards those who ha ,.e ;.pontancously given their fellow-members the bcncfils of their knowledge, or the results of their experiments .

In selecting those to receive recognition the Council ha ,.c kept in mind the fact that general or cv~n elementary art icles have their place in this J ournal, as well as those of a more technical character.

* * * * B.E.R.U. CONTESTS

Allhough these ever-popular Contests are not scheduled to take place until next February, we arc, as is customary, includ ing in this issue the rules and an a rticl<• describing the changes which lwvc heen introduced. \Vi lh an all-round increase in \Vorlcl I)~ Contests we believe members will join with us in expressing the hope that the lead we ha ve gi,·cn, in reducing the period for our Empire Contests, will be followed up by other Societies in terested in such events. The rn:m B.E.R.L Contests should, under the new arrangements, receh·e e,·en greater support than in the past bu1, in order to make thcni successful, it is the duty of every member to begin advertising them 10-clay.

* * * * REPRESENTATION

By the end of this month we trust that e,·ery important town in the British blcs will ha\·c elected its Town Reprc:-entati\'e for I !):3!l. See to it that the ,·ery bc:.t man is to be gi\'en the chance to keep the interests of the ociety at high pitch in your town.

J. c.

THE F . ... ~ R. BULLETl.\J, ~ovember 1938. 257

Optimum Plate Tank Values By c. \\'. SLACK (G5KG).

0 1\E of the most ill-used and abused part~ of a radio fre11uency amplifier is the plate tn.nk circuit. It is usually dismissed with a few

words in man\' text books, which seems u11fort11nate when we con; ider that it is from this section of the circuit that all the power output is obtain~'(). Further, it is here that a ll the e11ergy to be radiated is stored .

In lhu case of audio equipment we can compare the µrimary of the output transformer lO our tank c1rcuil m question. To obtain good-quality and inu:lligible speech thil> winding mul.t Ix· con,,truclL'd liO that it will operate under opllmum cond1t1on,,: if this is not done bad quahty and poor output will result.

\\'hen liO lllC of the J{.F. tank circuit;, which uc spccihcd from time to time a re examined, it is to be wondered that any output is obtainl'tl under certain o( the conditions in which they arc expected to operate.

Th<' present tendency amongst amateur:. is lo employ tL " ready-made" tank inductanco, with no more speci fication than that " it is suitable to operate on one specific band." ~o ment ion is made of the lype of circuit it is designed for use with, or whether split stator o r ordinary condensers arc to be used. Furthermore, no indication is given as to whether push-pull or singlc·-ended operation i~ intended a nd never is the plate resistanc:1· or plate voltage to plate current ratio mention<.'(].

An investigation will quickly prove that the plate t.rnk circuit should be operatt'd under optimum condiwons in order to obtain n1;1,1mum output and to do this t11e above condition~ mu:,t be carefully obscn ·ed.

Optimum L-C Ratio

If a !ugh tank impt'dancc is used with large g rid bias values and excessive excitation voltages, a large proportion of output power may b~ convert<.'<! into harmonic frequencies. These harmonic frequencies arc of no practical use in the s tage "hich feeds the radiating sy»tem and are of no use for communication purpose:, on the band in question. Also <LS our bantls do not altogether fall in harmonic relationship, it is quite possible, if harmonics arc radiated. t hat we shall be confronted with the probll'm of off-frequency operation. Additionally, a ll power which is genera ted in harmonics is wast(.'(! and if the tjuantity is such as to cause circulating currents, a large falling off m cllic1ency ";11 n~ull. Therefore, any :.teps that can Ix· taken to n.'()ucc harmonic output will result 111 better cffic1cnc\'. h should also be remembered that if a lower · L.1nk impedance than nccessan · is u:,ed, a low tmn~fcr of energy will rcsulr. •

From these considcration:s it follows thal there must be an optimum pomt in the adJu,,tmcnt o f plate t ;1 nk circuits where a maximum tran:.fcr o f energy can be maintained with low harmonic output. This is known as optimmn L-C ratio.

T he plate ta nk circuit. can be d escribed as analogous to the lly-wht!cl used in engineering. where the Hy-wheel is used as a store house for the

energy output from a ny type of motive power. When a fly-wheel is designed it must be of such dimensions as to be large enough lo supply an efficient transfer of the stor<.'<I energy to any load that may be applied lo it, but it musl not be so large as tO apply a damping effect to tile source o! energy. In other words, the Hy-wheel, a lthough s111liciently large lo maintain an cflicil•nt output or power, should onlr require a minimum of energy o r power to maintain the " fly-wheel cltl><:t. .. So it is 111 the case of the plate tank circuit. .-\s with the th--wheel there b onh• one coirut tank circuit for any one gi,·en set of concht101h. This conMdcration is ,·ery impo rta nt in tht• ca-.c o( modulated ,,ystcms " ·here large fluctuations in output occur and where, for best results, the output must be of a lml'ar character.

The optimum L-C ratio to be u~l'<I is governed br the ratio o( the D.C. plate , ·oltagt· lo the O.C. plate current feeding lhc final amplifier. For a given input the higher the plate voltage and the lower the plate current , the higll(·r the L-C ratio rct1uircd, and 1•ice versa. I t i ~ l hcrdoro only necessary to know the plak volta~·· and plate current ratio, or t he D.C. resistance, to determine the amount or inductance and ca1)acity required to obtain resonance at the desired frequency. so tha t optimum operating conditio11' arc observed. This can be brought about by calcula ting the capacitive rcactancc of the capacity in question a L the desired frequency and, as Ill resonance, this i' eqnal to the intluc ti\'C rcac ta ncc. Knowing tlie inductive reactancc, the inductance can be comput~'<I and from the inductance the physical duncnsions o[ the coil requirt'<I can be calculated.

.\s the value or capacity is inwr"ch· proportional to the frequency or, co1werscl~-. directly proportional to the w<welength, it makes it pol!siblc to express the capacilT iri micro-micro Jarads prr 111(/re. Thus, to obtain the required capacity, a ll lhat is required is lo multiply the number o f micro-micro farads p~r metre by the wavelength in metres. The number o( micro-micro farads l'>C r meter in relation to the plate voltage-current ratio i ~ also governed by the type o f c ircuit employed in lh1' ti n ;~! am~lifier. For instance, in Lhe case of :i ncutrahscd smgleendcd amplifier the capacity and indnctanct: values employed would be entirely un~uitablc to g i,•c optimum push-pull condi tions.

Before proceeding further 1t "ill not be out or place to show what a \\ idc vana t1on of conditions exi,t :.o far as plate tank circmb .ire concerned. ln telegraph,- t ransmitters concht11Jth arc generally no t so bad because no attempl is made lo confom1 the O.C. plate re;,istance to any g1n·n set o( circumstances. but in the case of 'phom· operation. the O.C. plate resistance mu:,t be of .1 definite \'a.Jue so that efficient match is made lo the modulator. Usually the operator of a 'pho111• tr:rnsmitter in his c•ndcavour to obtain good modulation. forgets the tank ci rcuit, yet it reqni rr:; just as carelul " rn:ilching" as the modulator, if efficient R.F. output is to be obwdncd. In t he case of the t c·lcgraphy transmittc·r the linal a mplifier is generally

258

ck~1gnl'tl :rnd operated according to tltl' ~pl'Cifications laid down lw the maker of the ' ·al\'e. In other words, the valve i3 operated under optimum conditions. I l is very doubtful, however, if tlw ta nk circuit operates in· the same way, especially in the case of multi-b~nd transmitters.

A Pra ct ical Caso

I.cl us now look at a circuit using a valve with a l>.C. plate resistance of I 0,00() ohms in single· ended operation and designed fo r multi-band operation. The optimum \'alues of inductance .111d capacitr for 28 :\!c. operation arc 2.5 micro henr\'s and 13 micro-micro farads, rci.pccti,·ely. ( I lo,\ these \'alue,; were arri\'cd at will be described briefl~· later.) For 1.7 ::\le. opcrauon undC'.r the same conditions a capacity of 220 IAILF with ~n inductance of -40.0 ;i.H would be rcquirt'(I. I t w1ll he l>l'Cn immediately that it would Ix• impo~~ible to exp~'Ct a 220 tJ.ILF condenser to open out to 13 µµ.F, ig1rnring altogether valve and ci rcuit capaci ties. L'sually :i I 00 µ.µF per section split -stator condeus~r is specified in a circuit of this t ype and to tune to the 1.7 :\le. band an inductanc1• o f about 177 µ 11 would be required a nd this would requi re to haw n reactancc of about 1,880 oh111s at 1.7 .:.1c. For optimum operation and best efTtcicnC)' the reactancc slio11/1l be about -435 ohms. To obtain optimum operation using an inductance with a rcactancc of

. 1.880 ohms, the plate D .C. resistance would require to be adjusted to about 44.000 ohms which means a plate current ratio of 44 : I. 1 n the cas..· of a T55 ' 'a l\'e the plate current would ha,·c to he reduced to 3~ m.\. at 1,500 Yolts.

Oftt•n when a vah'e which has a D .C. rcsist;mce of. l>.'ly. 10,000 ollillS is working under optimum telephony conditions, it has to bo adjust ed to. say. 5.000 ohms to match up to the modulation transfornwr. The rcactance of the LC conditions would then require to be about 220 ohm~ for correct opcr;ition.

These examples indicate how wi<h' of the mark the designer is liable to bo in choosing tank circuit , ·:tlucs.

Lt 1s beyond the scope of thil' contribution to c-.:plain in great detail how the \•ahw-. of micromicro farads per metre a·rc arriVl'<I .1l, hl·caui.c to

' ....: I . "\ "\

.)0

""' I"

I'\ •

""' I" ~

r\ ~ .. -' -- ' , _ '

{ '-'\

" .. ~

"\. "\ I -

""' " r-. .

I"- ~

. "' .. ., ..01' O'T 10 .. .. . ,,. FIG. 1

Chart fo r computing o ptin1un1 capacit y oe r mttre. .. A" • inKle ended: u B 0 push .pull /inn/ ampli fie r

THE T. \So R. BULL£Tl.V, Xo,·ember 1938.

do so would lll'Cl'"•tlate going into a \'Cry length\' de:;cription cntailm~ a masi. of algebraical formu la.which would ha,·c no direct bearing on the article itself. In any c:1sc the values themsel\'es vary somewh:it :iccording t-0 the opinions held br those who have investigated lhc subject. The writer would mther not attempt to lay down any hard a nd fast rule on this part icula r matter but would prefer to sta le that the particular calculations used to produce the values or micro-micro farad per metre refcrn.'<I to herein and employed to produce Fig. I arc based on a "Q" \'alue of 12 when the amplifier is und..-r operating conditions and fulh' loaded.

The term " O .. \'alue, which can be briefly described as a inca~urcment of the " ~oodnc,.,.. " 0£ a tuned circuit or as an indication of " sharpne~s of resonant;c," can bo <'xpresscd by the formula :

2r.f L <1=-H-

Those readers who wish to work out for thcmsclvc~ the \'a lues shown in f"ig. I w ill find that for curve (A) t he \':tlue of micro-micro fornds per metre for :i plate voltn!(e/current rat io of unity is 12.5 µµF per metre. so :ill that is required in order to find the value for any other ratio is to dh·ide 12.5 by the new ratio.

Example : \\'hen Va/ Ja ratio is 5 or D.C. plate resistance b 5,000 ohms, the " micro-micro farads " per metre \'aluc for curve A will be 12.5..;-5 = 2.5 µ;.i.F. In the ca;;c of cun·e B the \'alue at unity 1~ .i µ;.i.F per metre. Readers who wish to make up a chart similar to Fig. I will find their task simplified if they use logarithmic graph paper.

Now to proceed. all that has to be decided is whether single-ended or push-pull operation is to be employed. If split stator tun ing is used , the values gi\'en have to bo multiplied by two as well as by the w:t\'elength in metres, this will give the capacity of cncli seclio11 of the split st:itor condenser which will he required to bo in mesh whctl resonance at the desired frequency is obtained.

Pr:actlcal ExamplH

Dctaib Wiii now bo i::h·en or the procedure U'ietl

to calculate (a) the plate current / plate \'Oltai;:e ratio: (b) the plate D.C. resistance; (c) the capac:iti,·e.and induch\'e rcactance : (d) the 10ductanee 1n m1crohenr)'S; and (t) the way in which the physical dimensions of the coils can bo obtained.

(a ) Pl:ite voltage. plate curren t ratio is obtained by di"iding the pl:ite voltage by the pl:ite current when the fiual amplifie r is full y loaded and operated under the correct conditions for the \':tl\'e in questio11.

Thus:- \ ':i la

Example : I .OOO volts _ a ratio of IO-I IOOmA

(b) Thi:; formula will also gi\'e the D.C. plate resistance : Thus

\ 'a I .OOO I ,OOO I .OOO Yalii':\ x - 1- or IOOm.\ X - 1- = 10,000 ohms.

ll 1s thert•fore i:asy to obtain both t he plate voltage/ current ratio and the D.C. plate resi~~'lncc of an amplifier under any working con.d 1t1on~. Knowrng the plate \'Oltagc/ current ratio, the optimum capactt)' per metre can be obtained from

THE T. cS- R. IJULLETJN, )iovember 1938.

the chart (Fig. I) for the type of amplifier it is intended to use. .\fter this has been calculated the optimum lank capacity can be worked out for any freq~ency and for any type of operation ('phone or conunuous wave). ln the 'phone section optimum values for any circuit can be obtained using either anode modulation, control grid, supressor grid or class B linear modulation.

(c) When the optimum capacity is known for a given set of conditions the exact \'alue of inductance can be calculated. For example, consider a Taylor T.55 valve working under optimum conditions (1,500 \'Olts at 150 mA on the anode). Jt will be apparent that the plate volts/current ratio is 10:1, and that the D.C. plate resistance is 10,000 ohms. On examining Fig. I it will be seen that the capacitv for this ratio is 1.25 µµF per metre. t herefore the optimum plate tank capacity for 40 metre operation wi ll be:

1.25 X 40 = 50 µµF. If split stator t uning is used, that value is again

multiplied by two giving 100 µµ.F, an<l this capacity represents each section of that condenser. N~w with the optimum capacity known, i t is

reqmrcd to find t he value of inductance which will resonate with exactly that capacity. To obtain this we must first calculate the capacitive reactance of that capacity at resonant frequency, beca11se at reso11a11ce the capacitive rcacla11cc must equal the i11d11ctive 1•cactancc. Therefore if Xc equals X l, then the capacitive rcactancc of 50 µµFis calculated in the following manner for 7.5 :\le. operation:

JOG Xc= 2;Tc

\\'here: 101 equals I ,OOO.OOO 2,, G.2S

f frequency in megacycles (in tbis case 7.5 :\[c.)

C capacity of condenser in micro-micro farads.

259

T • I ,OOO.OOO herefore Xc= 6.28 x 7.5 X50 = -127 ohms.

and as at resonance the capaci th·c reactance must equal the inductive reactance (to produce a pure resistance) Xc equals XI.

I By the formulre 2'l': fL~ 2~ fC

therefore to resonate with 50 IJ.l.LF at 7.5 :\le., the inducti,,e rcactancc must be -1 27 ohms.

(d) To find the. inductance required {in microhenrys), the followmg formula is used :

Xl L = 2,, L\lc whenXl= 2r.IL

Therefore: L - -IZ7

= 9.1 micro-benrys. - 6.28 x 7.5 (e) As we wish to construct a coi l having exactly

t hat value of inductance, we may calculate its physical dimensions by using the formula

~ . I :JA H H:l . =v o.2 ,\~ x L Where : L is t he inductance in micro-henrys

A mean diameter of the coil in inches

B ,, length of the winding in inches N .. .. number of turns.

The tables given in Fig. 2 show the number of t urns required to make each inductance a standard size ?f 2.75 inches diameter with a winding length of -1 mches, this being a convenient size for a wide range of frequencies and input power.

Therefore, when : L is 9. 1 micro-henrys A .. 2.75 inches J3 .. -I inches.

:-\- . I 8.25 + :.lG ~ 9 1 _ . l2Gi 16 turns to the • - v 0.2 X 7.56 · - V nearest whole number. When a coil has been constructed to these dimen

sions, all that is now required is to make sure that

VALUES FOR SLNGLE-EXDED OPERATIOl'> Plate D.C.

I I Resistance Optimum Capaci ties in Optimum lnduc'lance Values Number of turns to produce optimum in Otims. micro·micro farads. in micro~henrys. incluctnnce ''hen wound to a diameter Va/ la I of 2. ;u inches spaced 4"'.

Ratio \\'nvclengtb in metres. l Wavelength in metres. D ivide \\'avelcngth in 1netrC$.

by 1,000. 160 1_~_1 __ :.?_J_:~ .. J-~~J_::_~l~l~I 20 1_10 __ 1_::_ ~~~l~l~l_s __

10,000ohms. :!00 J OO &O 25 12.(> 6.25 36 18 9 4.5 2.3 1 ~ 32 :!:I 16 Jt.5 8 6 9,000 .. 224 112 50 28 H 7 32 16 8 4.0 2.0 1.0 31 :!:! 15 11.0 7.5 5.5 8,000 .. 250 125 02.5 ~l.25 15.6 7.8 29 14.5 7.3 3.6 1.8 O.!l 20 :!L J.1.6 10.5 7.0 5.2 7,000 .. 286 H3 7J.r. 35.8 17.8 8.0 26.5 12.7 6A 3., 1.6 o.s :!S 10 H 11.5 7 •J.8 6,000 .. :13(} 108 84 ·12 21 10.5 21.5 10.7 5.8 2.9 1.4 0.7 !?!> 18 12.5 u.o 0.3 4,5 6,000 .. 400 200 100 50 25 12.r; 18.0 9.0 4.5 2.3 1.1 0.6 :?·I 16 12.0

I s.o G.O 4.0 ·i,000 .. 500 250 12G 62.5 31.3 15.6 lU 7.2 3.6 1.8 0.\1 0.5 21 15 10.6 7.6 5.2 3.8 S,000 .. 660 333 160 8$ 41.5 20.7 u.o 5.ft 28 1.-1 0.7 0.4 18 13 11.0 6.5 4.5 8.3

2,000 .. 1000 500 250 125 62.5 :11.3 7.2 3.6 1.8 0.9 0.5 0.3 1a 10 7.5 5.0 3.8 2.5

VALUES FOR PUSH-PULL OPERATION

10,000ohm.s. 04 8:! lU 8 4 2 113 I WO I ~, I H.2 I 7.1 :u; 58 oil :!U 20.5 H.5 10.3 (l,000 .. 72 30 18 u 4.5 2.3 100 (;() 25 1:.t5 6.3 3.2 !H 38 :!7 19.0 13.5 9.5

8,000 .. 80 40 20 10 5 2.5 !)() 45 22.5 11.3 5.6 2.8 51 37 25.5 18.5 12.8 9.3 7,000 .. 92 46 23 11.& 5.8 2.9 78 39 19.5 9.8 4.9 :?.5 48 a4 24 ti.O 12.0 8.5 6,000 106 53 26.5 13.3 G.G 3.3 GS 34 17 8.5 4.3 2.2 45 32 •l'> ~ 16.0 11.a 8.0 .. ..... ., 5,000 .. 128 (l..I 32 16 8 4 57 28.5 I H.3

7.1

I 3.6 l .8 41 2\l 20.5 H.5 10.3 7.3

4,000 .. 160 80 40 20 10 5 45 22.5 IJ.3 5.6 2.8 1.4 3; 26 18.5 13.0 9.~ 6.5 3,000 216 108 64 :!i 13.5 6.8 33 IG.5 8.6 4.3 2.1 l.1 31 •>O 15.:i 1LO H .8 5.5 2,000

.. 320 160 80 40 20 10 2:? Jl.O 5.5 2.8 1.4 0.7 20 lS~o 13.0 9.0 6.5 4.5 ..

Fig. 2.--Th e r eai•tance value• repruent the D .C. plate resistance of th e final amplifier when fully l oaded. All capacity values are in mic ro•micro farad• and all inductance values in micro-henrys . The number of turn.t given i n each caae will p roduce t he • tatcd inductance when wound to a diameter of 2.75 ins. and the turns •paced out to a le ngth of 4 ,·ns. T he condenser v alue• are fo r •inglc-•cction condenser.s . II •Plit stator conden•er• are u•ed the capacities , ;uen mu•t be multiplied b)' t wo. Th is will give t he a i:e of ea ch section of the aplit atator conden•er.

Note.- The ualue• giuen in this chart only hold Kood for plate-ncutrali• ed circuit1.

260

the tank cond('nscr will have suflicic11l c;tpacily lo tune to the required frequency. Wo ca11 l hcn be sure that at resonance, the optimum L/C r;ttio has been accomplished and the amplifier will deli\'er maximum output with minimum harmonic content.

It will be noticed that , although the optimum capacity 1s t he fir.l pomt to be considered, 1t can be forgotten as soon as the inducta11ce "alucs arc obtained. It will also be seen that it is a simple matter to construct a coil or defini te 111ducta nce. ' Vhcn that is acl11c\'ed, the capacity automatically adjusts itselC to the optimum capacity al resonance.

As some reader:. may not wish to take !he trouble of making all the abo,·e calculations themselves, the writer has compiled a chart, Fil(. 2, which gl\·es all tlie required rnformation needed for frequencies from 1.7 to 56 '.\le .. a nd \\,th plate D.C resistances ranging from 2,000 lo JO .OOO ohms. Both ~1ngleendcd and push-pull ci rcuits arc catered for.

By carefully Mudymg the ch:irt a choice or T./C values can be made for operation near to optimum conditions on a number or bands, although il will be evident that it will be difficult to obtain optimum

A Useful Three Circuit Oscillator

BY J. TROY (G'.\ISHJ)

THIS simple :i.nd cfiicicnt oscillntor has hcen in use at tho writer'!! station for ~omo considerable lime and has a.lw;iys given consistent

and satisfactory results. The three circuits covered a.re (1) Straight !Jcntode Crysl<il, (2) Tritet, (3) E lectron coupled. The sketch shows the circuit employed.

Any of the three circuits can be brought into use by a novel method of :,\\'itching. Credit is due lo E IGG a nd EISl\'1 for lho Jund;imcnta l hasis or the circuit, but in thoir case il .is used as E .C. or pla.to to grid crystal oscillator. Tho vnlvo employed is a. 6L6G and lho oulput is tho sumo whon oither circuit is in uso. The s tability on E.C.O. is equ:\l and all stations worked could detect no difference in the qua.lily of phone transmissions whilsl all C.W. reports were T9X.

L.l.

The Three Circuit O•cillator.

CJ. 300 µ.µ F Rl 250 ohm• 2 watt•. CZ. .005 µ. F mica, R2 100 ,000 ohm• 1 watt. CJ. .0001 µ.F mica, RFC Pie wound chokr. C4. .002 µ.F' mica, SW DP DT ••uitth.

LI ia wound on a I t in. former and con•i• t• of 14 turn• 0 ( No. 20 SWG DCC wire, cfoae wound. The cathode tap is made t wo turn• from the earth end.

The cbango from E.C.O. to cry:>t<\l is effected by me;ins of :i DP DT switch, :ind from straight

1'HE T. 6- R. BULLETJ.Y, Ko\'ember 1938.

conditions on more than two bands if the \'Oltagc/ current ratio remains constant. It will a lso ho noticed that optimum conditions for operation 0 11

the frequencies of 28 and 56 :'-le. will be difficult to obtain when val \'e a nd circuit capacities arc taken into account, which of course explains the desimb1hty of using special ' -ah·es and c1rcmts for these frequencie5.

A careful study of the chart ,,;ll show the reader that it is a good plan to construct separate tinal amplifiers for each frequenC)' band, for only th..:n can lrue optimum conditions be maintained. l t 1-. also ad\'antageous to construct separate induct· ances when 'phone operation is desired, especially when the plate ,·oltage, current ratio has to be altered appreciably from the normal C. \\". !;Clltng-. m order to " match " the D.C. plate resistance to the impedance of the modulation transformer Tf tins practice pre\'ailed the writer belie,·es th;it ma ny of the present " broad " 'phone signals would disappear, being replaced by good transmb,ions which lune sharply and occupy only a minimum of sp:icc in the spectru m.

Pentodc 10 Tritct by t he usual method of shorting the cathode condenser. One of the mo\'ing \'ancs of this condenser should be bent slightly, so that when the condenser is turned to maximum capacily it automatically shorts the fixed and moving vanes. A slow motion dial will be found of great ad,·antage for this condenser. T he calhoclc, on E.C.O., is tuned lo :l.5 l\lc. doubling to 7 ;\Jc. in the plato c.i rc1til.

To use the straight Pcntode ci rcuit, the cathode condenser b shorted a nd t he crystal switched into circuit. \\'hen the Tritet circuit is required. the cathode coil ·should be replaced by one suitable for the crysta l in use. The cathode coil is wired a.cross pins l and 3 as shown in the diagram. Cl is necessary to point oul lu:re that a. re liable frequency meter of approved lype should be employed whon lhc E.C.O. circuit is in use. The abili ty lo make easy and rapid changes of circuit is ono or the grea t features of this oscillator t> nd it will :imply repay the cost and time of building it.

A Special J.B. Condenser for U.H.F. Work

T he H.F. output produced by " The l "ltra'.\ lodcrn 56 '.\le. Transmitter " described in the April . 1938, BliLLJ::TI:-', was so high that, with no aeri:il load applied, there was a tendency for lhl' P .. \ . tank conden~er to sp;i rk o•·er on occasion:.. This cftect, which could k-ad lo an arc and consequent damage was cured by substituting a sp1.:cmlly designed condenser made by J ackso11 Brothers. This condcn~cr is similar to t he origina l model. except that double spacing is employed. lt is of the split stator type, with Kcramot insulation and the capacity is 14 µ;.i.F. each side, giving ;i working capacity of approxim;itcly 7 µ;.i.F.

I t i,; made to special order at a slight extra cost and can be strongly recommended not onl~· for the transmitter in which it is employed, but also for any 56 )le. appara tus of a similar type. The concknser posse~ very low losses and has a , -cry low minimum capacity.

TllE T. G R. Bl:LLETIX, So,·embcr 19:l8. 261

A 56/28 Mc. A.C. T.R.F. Receiver

READERS may ha\'e heard of a pro,crb to the effect that " there is reason in all things"certainly when a mdio amateur builds a new

piece of gear he or she has a good reason for so doing.

In the present in~tancc the writer was studying a recent catalogue of T1mgsra111 vah-es. a nd two types in particular c laimed his attention. The first was the type VP-IB, a variable-mu H.F. pcntode rated for 250 \'Oils on both anode and M:rccn, and with the Ycry high mutual conductance (for this type of valve) of -I uA/\', combined with an anode impedance of one megohm. Taking mto consideration that the Ya.kc is fitted with a grid top cap, gi\'ing a low input ea.pa.city and high input impedance on ultra-high frequencies, it became obvious that here was a valve which, when included in a carefully designed circuit, would undoubtedly gi\'c a definite gain at ultra-high frequencies. The

---

The Coll• _\bout the same lime a new type of coil had come

lo tht: writer's notice, which, like the vah·cs, wa.'! 111.ide in such a form a.<; to render it outslandingly suitable for U .H.F. work.

The coil referred lo is the " Oenco," as ad vertiscd in this journal, <1.nd its spac ial q1rnlitics arise from the fact th<1.t the former, of I kin. diameter, is made from Trolitul, as abo is I he base, no other material besides the metal pins, supports, etc., being introduced : e,·cn tl1e \'arnish to hold the turns firm is Trolilul. The metal pin-. arc very small, and ll1e leads from the coil run strai~ht down through them by a ,-cry short n.nd direct path, a.voiding CtLrls :intl loops, which means that the induct.mace is concentrated in the.: cll il itscll, and not in the connccling ";res.

The reader is dou btlc~s awaro of the rc.:mark;\blc 1·lcctrical qua.litic:-. of Trolitul. It is dill11;11ll on

Top deck ui~w of Power Unit and Detector sta•~ of Rec~iv~r.

" Acorn " is. of course, the ideal, but its price makes it prohibiti\'e to the majority, whereas the \ ' l'-IH is \'Cry rea.woably priced.

The second \'al\'C was the HL-l)(, a medium impedance triode, also Possessing low input and output capacities, and ha\'ing characteristics 111d1catiog that it would make a good detector.

It is well known that mains-operated ,·ah·es are -..upcrior in practically all respects to battery trpes, this being due to the more generou~ electronic emission a\'aila.blc The idea of ha\'in~ a rccei,·er specially for the higher frequency bands, running off the mains, and quite independent of batteries, was ,·ery attractive, especially since the performance would undoubtedly reach a high standard.

It was therefore decided to turn the mentally pictured recei\·er rnto concrete form, and as the design and component values for 56 .\le. operation would also be suitable for 2S .\le., and would ensure first-class results on the latter frequency. it "-a_" furtller decided to include coils for both band<>.

tho ultra.-hii,:h frequencies to obtain c1rcu11~ of high dynamic 11npcdancc. but, by the use of thu coil ~ 'Pecilied, with their extremely low lossc~. an impro,·cn1<:nl is undoubtedly effected, anClfllCllCe.

The circuit. on the whole, follow-,, that norm.illy employed in any T I{ I·. rcceh·cr, but special attention ha' been paid to apparently small point.swh1ch point,, make a con~idcra.ble difference on the ultra·l111:h frequencies

The R.F. Su1e lt 1s of Iii.tie use employing a high gain type of

R.F. amplifying , ·ah-c unlcs:. one cns11res tha t it is oper;ned under conditions which will, wiU1out question, .r;:i,·e the gain indicated in the literature which u,,ually accompanies it . On lower frequencies hbcrtic~ can be taken m ~C' era! directions-for in~tam.:c, cathode bias rc~1stancc and screen voltage -and any falling oil in performance ";u probably be d1lficult to detect, but in the present. instance, opllmum \'alu~. <L'> near '" po-..,1blc, mruil be used

262

t hroughout. in order to ensure that. the R.F. valve acts as an amplifit:'r, and not merely a.s a. buffer between the aerial and the detector stage.

For the same reason the input. circuit. must be fully tuned, and not of the aperiodic type, employing a choke or resistance only in the grid circuit.

As tuning is not unduly critical band spreading is not essenlial, pro\'iding a good slow-motion dial is used, and, as the tuning condenser is of greater capacity than the main one in the detector stage. it cannot be ganged to the latter. but is controlled by its own knob and dial on the panel.

The screen is fed with a voltage ''et')· nearly equal to that. supplied to the anode, the series resistance R.J sho"·n in Fig. I being in lhe nature of a decoupler. ln p;c;sing it. may be said that thorough decoupling. to keep the H. F. and A.F. currents to their proper paths. is absolutely necessary in a. receiver of this type.

Tho Detecto• Staie As in a.ny other T.R.F. receiver, whilst the first

\'a.h-e gives a definite gain. the O\'erall w nsitivity depends largely on the detector stage a.nd on 1 he use of reaction.

TllE T . G R. NUU.E.TI N, :-Jovcmber 1935.

On the ultra-high frequencies all the components comprising the detector stage must be carefully placed to ens11re that all connecting leads are \"CIT short. As can be seen from the photograph, the detector val\'e i.; mounted horizontally, and the associated components ;~re arranged very clo;,e to it.

To enable the reaction condenser to be con\'Cnienlly filled. this i~ mounted with the rear facing lhe panel. so that it is actually controlled from lhc back of the recei,·cr. This is no disadvantage, a.sit b only u~ed for coa.r:.c ~elting. line reaction control being accomplished by means of a '-ariable resistance mounted ccntrallr on the front panel.

Band-spreading is. of course. c~cnlia.I. the band spread condenser being a Webb's " Economy" in>c. lhe original capacity of 15 µ.µF. bein~ reduced by double spacing, and using ooly one fixed and two moving vanes. The band set condenser consist:. of a Polar midget of 25 µ;.i.F. capacity, and its extremely snrn.11 si1c allows of il being mounted on a :.mall aluminium bracket. close to the coils.

Tho tuning dial employed is of a rather unusual lypc for this class of receiver, but is peculiarl~· suilcd for n~e on thc 28 and 56 )le. bands. where one i~ in Ute habit of lr;wcr~ing the whole band

Fi11. I. Cfrcuit of th e Rcceivn PO•tion of 28156 M c. A.C. R•c•ivu.

Keyed Co1npont11t1. CJ. 15 1iµF Midget va•iablc, llamma•lu11cl. C2. 15µ1t.F va•iable (••c/uccd tu p•r text), Webbs

"Economy ... C3. 2sµ1iF Midg•t T•immc•. type C.801, Polar. C4. 160 µµ F va.iab/c, tYf!• "E" Sirigle, Pola•. CS, 7. B. 14 & 17. 100 1iµF Ce•amic Cup type K ± S pe•

con t., T.C.C. C6. 9, 11, JS , 19, 20, 21. .0003 µ F type M. Mica, T.C.C. CIO, 13. SO µµ F. Ccrnmic Cup type K ± S per cent ..

T.C.C. CJ 2. 4 µ F. Elect•olytic, Polar. C16. .02 µ F Pape• Dielectric Tubular, Polar. CJB. SOtJ.F Electrolytic 12 volt wltg . type F. T .. T.C.C. RI, R11. ISO ohm• 1 uwll, Polar. R2. S,000 ohm• va•iable type V/1, Pola•.

Othe• Valueholder•. 2 :x 7 pin Ceramic. l x 1 p1

4

n Airsorung, Clix.

Slow Motion Dial (in d•1t•ee•), " Puturo," Pola•. Adiu• table ln•uloted Bracket type No. 1007, Eddy

atone. Flexible Coup/er, type No. 1009, Eddy•tone. Solid Coupler (fo• the reac tion Conc/cn•er) type No.

2005, Bulirin . 1 Slow Motion N ead w ith Knob Dial and Cur•o• , t)'pe No

1036, £ddy•tone.

R3. 1,000 o/1m• 1 wall, Pola•. R •I, 6. 5,000 ohm• t 1va11, Poln•. RS. 3 mego/1111 1 wall, Polci•. R7. 25,000 ohnu 1 watt, Polar. R B. 50,000 ohm• ua•iable type V4 Polar. R9. 500,000 0/1111 8 un.iablc ty110 Y4, Polar. RIO, 13. 10,000 ohm• 1 wall, Pola•. .RI 2. 100 o/11n• t wall, Polci•. RFCJ. .R11tlio F•cquency Cholte type 1010, Eddy<tone RFC2. .. .. ., t:»P• 1011, Ec/dyato ne. Vl. .R11di'o F•cquoncy Pentode t ype VP4B, Tung&rnm. V2. Top G•id T•iode type UL4g, T11n11a•am. V3. Audio F'Oouenc)' Pentode t y pe APP4C, Tungs-

Components.

4 lns ulotinll Pillo•• · tl in .. t ype No. 1029, Eddyatone. 1 Mid11et S tone/ OfT /ns 11/oto r, t y pe No. 1019, Edd,.•tone. 1 Ae•ial Strip, 1 L .S. Control Pone/, 1 Fu•• Plutt (1 amp.).

Clix. 2 G•oup B oarcl• C31 : I Mo11ntin1t St.Ip TZI, Bulgin. Coil• ancl Coil Bu .. T•olitul. De nco. Metol Wo•k, Parouui. Coble Bu1h Lt 262: Top Cap Connecto•• LI 175 , Belling

Lee.

THE T. 6- R. BULLET/.\', Xo\•ember 1938.

instead of just a. portion of it. The single large knob controls both the slow-motion movements incorporated, and, under steady pressure. the reduction ratio of 6 to I ena.blci. the whole dial to be traversed fairly ljUickly. yet, wilh the very snrn.11 capacity of the tuning coi l, without the possibili ty o{ missing weak signals.

A signal, a lthough heard , is usua lly pa.s~cd over. bul on reversing the rotation of tl11.: knob. lhc very slow-motion movement comes into operation a utomatically, and has a sutliciunt arc to enable an}' l>igna.l to be easily found and held.

The grid condenser is of tbe ceramic type, the grid leak being mountt.-d directly acros'i 1t, and

'.!63

Let it be said immediately tha.t whero ther arc shown they arc definitely required, as dctcrmint.xl by practical tcsL~. and the inherent freedom from instability is doubtless due to tbe fairly liberal u'le of these components. 1 t is often very difficult to place a mica condenser very closll to the vn.Jq: holder, in which ca$C it has lo be mounted as closu as is convenient.

Thll inductance of wiring affects lho by-pa.<<1 <\ction to a considerable c:-..-tcnt, so that, on 56 ~le. for instance, tho effectiveness in practice m;\y be much less than one would expect from thcorr. Where .0003 µF. condensers a.re indicated lhC\' sen·c a'> by-pas-cs on both 56 and 28 :\le .. but

B eloUJ the chn .. i• of th e 28-56 M c. Receiuer nnd iu a••ocioted Power Supp/y,

both held in their own \\·iring. so lhat they arc well »pa~cd from other parts. Capacity coupling to the H.F. stage, \\;th another ceramic condcn~er. is employed. The grid of lhc detector \·ah·c is lapped down tho tuning coil to pre\·enl the input impedance of the \"al\"e being placed aero!>:> the whole tuned c;1rc111t, the effect of which would bu to reduce the dynamic impedance of the latter lo ;i lower \'aluc, resulting in poorer efficiency.

T he L.F. Staao The low-frequency stage incorporates a hit:h slope

puntodc valve, and is rcsistancu coupled to the ·dclcdor. This stage follows normal practicll. but p1'l·c:~11tions against t)1c possibili ty of R. F. getting thrnugh to il have been taken. In consequence threshold howl, hand-capacity, and in:.lability of any :,Ort arc con:.picuous by their absence. .\ loudspeaker may be fed direct from the output vah·e, and. a~ the rccei\"er is intended chiefly for loudspeaker reception, a C/ir L.S. panel is fitted to the rear of the !>Qt. lf it is desired to u~c telephones. an output transformer should be connected externally to prevent 1bo anode current (which is in the region of 25/ 30 mA.) damaging the windings.

T he By-Pus Condensers Before considering UlU power supply, a word of

explanation regarding the by-pa~s condensers is ca lled for, as t hese arc inserted in ono or two unusual places, and a lso duplicated at cct'lain important points.

chietly on the lallcr band. The \'err :.mall ceramic condcn,crs which arc mounted right on the \·aln· holder, between the appropriate electrode and the calho<le. make a \·cry big difforence on tho ultra-hi)!h frequencies, even though the capacily used only .0001 µF., this being the Jarl{est \·alue a\-ailablc at the umc. The benefit b due not onh· to the very short leads reducing the inductive effect, but also to llw verv low losses of the condensers themselves. There· is little doubt but that if s i111il,1r

Clo•e up uiew of radio frequ~nc)' .sto•e of R~cciuer.

264

condensers arc added 10 existing rt•cch·ers a definite improvement will result , The writer believes that larger values arc now oblainabk-. and il would be well to substitute .0003 µ.F. for the .0001 µ..F. spt-cified, in which ca'e the mica conden,crs could \\Cll be <•mittcd.

Other lnterfu tine Points The benefits obtaining from the use of a raruo

frequcncy stage arc wl'll known, but if the buffer acl1on between the aerial and detector stage is to be maintained, and if in,lability from back coupling of the aerial (which is, of course, connected lo the R.F. stage) lo the detector b to be avoided, no 'ignals must be allowt•d to rt'acb the dclector except via tlw R.F. slag<.'. For this reason a metal rear panel is fttted in addi tion 10 the front panel, whilst the valve holdpr,, of the first two valves (which arc in horizontal positions) arc fitted lO small metal brackuls, giving additional screening.

Tho Power Supply The s lighlt',t tract• of hum in a short-wa,·e

receiver is objectionahll: , especially when ~\'nsitive tclophoues aro in ust•, a nd t hen; is no doubt that tlw dillicult y of remo\'ing hum completely is one of the rca;,ons why battery-operated receivers arc s till fa\'oured h\' amateurs who ha\'e mains available. -

The chit.:f types of hum arc three-namely, inductive, mo<lula.tion, and from insufficient smoothing. When the powt•r supply is built as part of the receiver ilsdf it 1s often practicaUy impo,.,.ible 10 prevent induced hum, especially where ,,pace is restricted, and it is always bulter to build the power supply as a. separate unit, and place it se,·eral feet a.wa.v from the n•cc.>i\'cr. :\lodulation hum is audible ,\·ht•n a receiver 1-.. oscillaung, and i<> u:-ually worse when the rccc1\'er is in 11-. most st·n~iti\·e tondition, i.r .. just :.horl of the point where o..,ci Jlal ion would cease. It is due to R . F. currents being in place, \\lwre thc.>y -.hould not be; for example, 111 the heater or powt>r circuits. Suitable by-pal>.•ing of the ,·a.kc heater-. "111 remove 1he trouble, but it is usually necessary \0 exlcncl the process also to the powt•r supply unit. In the present instance, partly throuRh thC' ample by-pa.,.,ing ust'd, and partly due to the use of a transformer fitted with an electros1atically scn.-cncd primary, no trouble of this sort ha~ been c•nco1mtcrcd.

The circuit C'mploycd in the power pack is of tbc choke input lype, giving a lowl'r voltage than that obtained otherwise, lnll having the advantage of giving a very steady voltage ind1·p1·11tlent of current lluctuations. This point i;.; wry important if smooth reaction control is to bt: obtained. The mains transformer :ind n:ctifyini:: valve aJro run under conditions imposing )c,,s strain thereby leading to longer life.

The s moothing provided is ample, and ensures complete freedom from hum. The transformer and chokes a rc of ll'earile manufacture, and are wl'll designl'd and lwautifully finished products. The transformer is specially interesting, in ,;ew of the fact that either 4 or 5 volts is available for heating tht• rectifier valve filament, whilst the normal 4 volts for the other valves mav be increased 10 6.3 for octal bas<• \'alves. e tc. ·fwo \':tlues of high-tension ,·oltage arc obtam:iblc, the 350-volt winding (each side of zero) being tapped at 250 volts.

The power supply unit is protected by a 1Jelli11gLee fuse in the high-l<•n,ion centre tap, and by a C/ix fused plug for connecting to the mains.

THE T. 6- R. BULLETIN, .:-;(wember 1938.

Construct ion

The rcCC'iver proper is built on an aluminium chassis measuring J()• x 9• x 2r. The front and rear pan<:ls measure 10• x 9•, and it i:. necessary toen~urc that holes made for 1be ,·ariablerc;,istances, etc .. in tht: chas,,is correspond w11h identical holes in the panels. Jn addition, a screen measuring 9' X 6! •, and two valve-holder brackets, 3• x 4 • (RF.) and 3• x 2* (detector) are required. All, t•xcept thl' two brackets, may be of 18 gauge metal ; the bra1.kl•t:., which only have the bottom fianges to support them, being of 16 gauge. All lhe metal work, including the chassis for the powt'r supply unit, may be obtained ready drilled, and with all holes, including the' large one for the dial escutcheon, cut out. The supplit>r is E. Paroussi, 10, Featherstone Buildings, lligh Holborn, London. \\'.C. 1.

A sketch showing the position of thr various parts is n·ndercd unueccssary, as the photographs clearly 'how the gC'1wral lay-oul, hut to ht>lp intending con,tructors particulars of the actual ,pacings bet ween components, brackets, etc., a ro a~ follows:

Radio-freq11e11ry Slagc.-Co111partmcnt measures S- x 3". Screen fixed 3 ins. from lcfl hand side. YaJ\'c-holdcr bracket fixed 1 in. from rear. flush with screen. Valw holder (centre) 2 ins. above chassis. Condenst·r bracket, 2J ins. from front (slow-motin11 head occupies 1 in .. flexible coupler Ii ins.). Centre 2 ins. from left-hand ed!(t'. Two insulatinl! pillar<; holding coil holders, one 2! ins. from rear. o ther 3! Ill!>. from front (i.e., 3 in~. apart) near left-hand cclgc. J\c rial socket panel screwed to valv<··holdcr br:1rkt>t.

Delu/01 and L.F. S111i:es.-Dctcctor vah·c holder 2 ins. from rear, flush with screen. YaJ,·e centre 2 ins. abo,·e chassb. Coil holder pillars 3 ms. each from front and rear, 21 ins. from i;crecn. Reaction <'Ondt'n~1·r L .11 . holt•,, 21 ins. from scrc<·n: R.H.

r-.c

£

Fig . 2. Circuit o f tt p t!Citrl Power Su1111/y Uni't built l o motch

,.cccivcr.

C22. 8 t•F Electrolytic , Polar. C23. 6 µ. F Electro lytic, Pola r . C24. .01 µ. F Tubu la r , Po lar. Rl4 , 15. 20,000 o hnu 2 watt , Polar. Choke 1. 40 h enriu H . T .13, Wea ritc. Choke 2. 10 h enriu II. T .11 , Wearitc. Trons fo rm#r " Uniuer•ol," Weo rite. Valvelao /Jer 4 · pin A1'rap run8. CUx. Valve. In directly h ea ted t>•P e APV4, T un11ara m . S witch. Sin11le Po le On-OR T y pe S91, B u l11i n. Pla11 a n d Sock et. S-pin M u lti Connect or No. 1260,

Bellin11 Lee. Fus e Ho/Ju and 100 mA. Fu... No. 1045, B.tlin t: Lu. Metal work. Parous•i. Fused Plug (with 1 amp fu1u). Clix.

THE T. 6- R. BULl~ETl.V. :'.\"ovcmber 1938.

holes 11', ins. from L . H . holes. Rear hole:. I i ins. from rear ; front holes 3~ ins. from rear. (Xormal position of condenser is rc,•ersed, i.e., shaft projects to rear. ) Tuning condenser bracket 2• x ~·. \\;th flange. centre mounted -I ins. from R.ll. side, l t ins. from front; spindle I i- ins. above chassis (slot for condenser -t.r in .). Two snmll stand-offs on screen, mounted in line, 3! ins. apart, rear one just abo,·e vah'e-holdcr bracket. Band ;.et condenser bracket measures 2!" x 2•: fitted 21 ins. from R.11. i.ide, 3 ins. froin front. Electroh-tic condenser I} ins. from rear, and from R.H. side. Output valve holder 3 ins. from rear, I i ins. from R.H. side.

Fro11l Panel.-:\Iain dial opening a;. per instructions enclosed with it. Escutcheon ! in from top, I! ins. from R.H. side, 3t ins. from L.H. side. R.F. condenser S, 1[ head 2 ins. from L.H. side 3! ins. from top. R.F. gain control 2 ins. from L.Il. side. Reaction control 3 ins. from R.F. control. A.F. gain control 2 ins. from H.. II . side (all three I! ins. from bottom edge) .

Rear Pa11el.-Hole for reaction condenser shaft St ins. from side, -I! in!>. from bottom. Loudspeaker panel-as directed in leafl r t supplieclnear output valve.

Below llte Cltassis.-R.F. Croup board held by one valve bracket (detector) screw, and one ~pccially fitted. Other group board requires l\\O specia l screwi;, and is fitted between output ,·aJ\'e !-OCket and fm;t group board. Small bracket at rear, to which power supplies connect .

The foregoing gives practically all lhc information necessary to complete the construction . Both sides of Cl have lo be insula ted from thc chassis, this being accomplished by the use of an Edtlystone adjustable bracket, and llexible coupler. A -!-in. hole should be made in the screen where the anode leacl of the R.F. valve passes through, a nd suitable holes made below each valve holder to allo\\' the wiring to pass underneath the chassis.

\\'hen the coil bases ha,·e been fitkcl to the insulating pillars the amount of l11rl·a<kcl screw projecting abo,·e the fixing nuts must be nipped off. as thcr will otherwise prevent tbc cot! pms going properly into their socket:..

The height above the chassis of C2 may be suitably adjusted by interposing lwlwcen the bracket and the chassis a piece of t'llOnitc o f the proper size and truckncS!>. \\'here th1' hx111g :.crews pass through they should l>c covered with pieces of sleeving, and insulating washrrs usrd 11nrl('rneath, so that metallic contact with the chassis is prevented. Unless this is done a loop circuit is form ed. which will give ri ~e to peculiar effects. \\'lwn the receiver was first tried out. with the conden-.t•r bracket in metallic connection ";th the cha~SI'>, the tuning range was found to ha,·e a gap in 1t : a jump would occur from about 58 megacycles to a much higher frequency, but this effect completelr disappeared after carrring out the arrangement above.

It is desirable to mount the react ion condenser abo,·e the chassis by means of !-in. lengths of tubing (either chonite or metal), as this brings the connecting tngs nearer to the coil baM•s.

Wiring Up In apparatus of this type, \\'hcru the spacing

between many of the componcnls is small. it is wise to well tin beforeha nd all the soltlcring tags,

265

etc., to "hich connections ha,·e to be made, or, still hclll'r, lo judge the lengths of wire that \rill be requir('d (" 1th a little to spare, to be on the safe side), a ncl to solder these to the appropriate components before they arc mounted. Particularly in the case of t he coi l bases should this he done, as it will prove o( considerable help in completing the wiring up without diniculty.

It will Ul' found that Trolitul softens under the application of lu·at, but hardens up again afterwards, a nd is not. dl'lrimeutally affected. Low melting point res111-con·cl solder should be used, to avoid softening the Trolitul more tha n is necc~sary.

The \'alvc holders may be completely wired up before the brackets a re mounted.

The mrmg of the R.F. circuits mar be carried out \\ith 18 S. \\·.G. enamelled (not tinned) copper \\ire, a nd l>houlc.1 be short a nd direct.

Components should not be wired in series, but separate wires should be taken to the appropriate points. For example, the fixed vanes of lhe band set condc•nM'r could easily be soldered to one side of the fixed vanes of the band-spread condenser, the other side of the latter going to the grid pin of the coil ba~c. This, however, is inadvisable, and separate· wires should be taken to the coil pin from each condenser. \ \'iring in this manner will ensure greater stability.

The connection from the anode of thr H.F. ,·ah·e must be kept well away Crom adjacent metal work, a nd aho held rigid. The two msulating pillars mounted on the :,crccn above the detector coil enable llOth to be done. and also provide an anchorage for the grid condenser and leak.

The cera mic by-pass condenser C5 connect.. directly from the coil pin lo chassis, as shown in the photograph. The \\ires attached to the various other ceramic condensers should be cut as short as possil>lc, to increase their effectiveness.

The \ISO or group boards for the mnjorily of resistanct•s simpliftes matters below the chassis considerably, as well a-; giving a much neater appearance On the fir;,t one-termed, for convenience, th1• " R.F. Group Board "-arc mounted Rl, R3, R-1. C6 and Cll , whilst C9 connects from one side of HA to the chas~is.

On the other Group Board are found HG, R7, Rll , R l3 and Cl8. Cl9 connects from one fixing screw to R12.

In addition to the condensers shown, two of .0003 µF (noted as C20 and C21 in tlw caption below Fig. I) are connected from the lwnter tags on the pow1•r supply panel to the cha!<sis. l t will be seen that rxtensivc precautions arc employed to ensure nhst'nce of modulalion hum, a 11d it can be definitely stated that ther arc well worth while.

The rear )lt\nel will not be fitted unlil near!\· all the ";ring has been completed, the final OJX'rnt1ons being the connections lo the " Clix " loud-speaker panel.

Co nstruction o( th e Power Supply The chass1~ bearing the power supplr components

measures s· x s·. and the finish matches the rccei,·er chassis. Details of the spacing between components follow.

The switch for cutting off the high-tension voltage (whilst allowin~ the heaters to be left on) is mounted in the centr<i of one side of the chassis, which side is considcn•cl l he iron t.

The mnius transformer is in the rear lc!t-hand corner, with the plugs for connections to the mains

266

facmg the rear. To lhe left. of it is the 10 H enry mput. filter choke. One electrolytic condenser is mounted It ins. from the left-band side. It ins. from the front; the other 4 ins. from the front .

The 40 Henry choke is in tbe R.H. front corner; he valve holder practically cent.rat on the chassis,

and the Insc in front of ancl lo the left. of it. No mains swilch is fitted, as the special cormecting device on the transformer renders it. unnecessary.

Wiring up is simple. !t is only necessary to note C20, a mica .0003 µF condenser (which is .fitted direct from one heater pin on the valve holder to the chassis). and the po~ition of R14 and Rl5 (which arc identical resistances in series to give ;1dequate dissipation) between the junction of the two chokes and chassis.

The power supplies connect to a /Jelli11g Lu 5-pin socket on the rear of the cha~,i;;. a flexible cable ending in the plug being fitted to the receiver, enabling quick and fool-proof connection between the two.

The 2:'l0-0-250-volt out.put is uliliscd, and a very steady, well-smoothed D.C. supply of 180 volts Tcsulti;. If the 350-volt terminals arc connected the output voltage rises to 260, and the efficiency of the receiver incrca~es :.omewhat, but a slight amount. of hum becomes apparent, and the reaction control is not so smoolh. R7 must be increased from 25,000 ohms to 50,000 ohms in the latter case.

Ope ration ~nd Adjustment As may be e~-peclcd, a recei\"er of this kind.

employing high gain val \"CS, and very low Joss coils, is very lively to handle, and M>mc adjustment of the coils may be called for to obtain absolutely :,mooth operation.

For use on 56 )le. the aerial coil should consis t. of a two-turns grid winding, and, in most cases, one turn of aerial coupling. The laltcr may be either connected directlv lo tbe feeders, where used. or series tuned with a ·15 IJ.l.l.F. variable condenser, when a long end-on aeria l is used . Jn the latter case the lower aerial socket. is connected to the earth i.ocket. An eart h terminal should be fitted on the rear of the chassis, a nd, although an eartl1 will make little difference to sign:i l strength, t uning, etc., it should be used in order to ensure stability of the rccci\"er and power supply as a whole.

The detector coil windings for 5G )le. will be two turns grid and one turn reaction- the fact tbat oscillation can be easily obtained with only one reaction turn indicates, in -itself, the low loss characteristics of the detector stage. The tapping for the grid connection is made at the top of the turn nearest the grid pin, the connection itself being made by means of a 1311/g fo " Acorn " type valve clip. A crocodile clip should not be used, as the comparatively heavy mass of ferrous metal m the field of the coil will have detrimental effect s.

If t he wiring follow~ clo:,ely that of the original receiver the band set condenser \\ill be at not quit<' half capacity. Once the correct position has been found a mark should be made on the bush in which the spindle rotates, so that the setting nrny be easily found at any time.

On 28 ::'llc. the aerial coil should h:we fi\"e turns grid, and two turns aerial coupling : the detector coil .five turns grid, centre . tapped for the grid connection, and one turn reaction ; the latter being

TH E T. l- R. JJULLETIS, ~ovember 1938.

very clost· to the grid "inding. The band set condenM:r will be at just over half capacity.

The i.izes ~pccified for the coils and condensers will result 1 n the amateur bands being fullr covered. with a litlll' to :.-pare, on the tuning dial, which, being large, is easy to read. The tuning condenser of the RF. stage will only !ll'cd slight readjustment from one end of the band to the other.

The Alexandra Palace television and sound signals can be recci\·ed with the 28 )fe. coil in the R.F. stage, and the 56 ) le. coil in the detector stage, with the band set condenser at nearly full capacity . under these circumstances, however, the R.F. ~tage is acting in an aperiodic manner, the tuning condenser being set at minimum.

If regular reception is contemplated, either a larger condenser, of say 40 µ;.LF .• should be fin ed. or a coil, !>p<.-cially wound with four turns grid winding, M1bslituted. The coils a re obtamable in the correct sizes as specified from De11co, of Clactonon-Sea.

The recl! iver is operated in a perfectly normal manner. \ ·Vith the variable resistance controlling reaction Sl•t at lhe mid-point o f its movement, the reaction condenser should be adjusted (from the rear) i.<> that the receh·cr oscillates. Further critical control is then carried out with the variable resistance.

Hanel capacitr is conspicuous by its ah~cncethere is not the slightest tr.1ce of it , and the metal work may Ix: touched whilst a i.ignal is being received without changing the note in the ~lightest degree. This may be attributed to the large amount of screening incorporated, a nd thc care which has been expended to ensure that. the decoupling- and by-passing arrangcnwnt~ are thoroughly cflcct ive. The background noise level is vcrv low.

The rrsults obtained from the receiver have come fully up to expectations. At the time of writing the receiver ha!> only been in used for a short period, but already on 28 :\fc. signals from five continents have been received, whilst on 56 l\ lc. the signals ui.ually hl.'a rd in Bristol have gone up considerably in strength. C. \\'_ signals from G6FO can be read casih- with the reaction control backed off well bdo\,. the point at which oscillation commences. lo~addition, telephony signals from GTL2, a police station in the )forth of England, have been received a nd copied at good strength.

LONDON MEETING

Wednesday November 23rd, 1938 at

1.E.E., SAVOY PLACE, Victor ia Embankment

Tea, 6 p.m. Commence 6.45 p.m. LECTU RE:-

RECE NT VALVE DEVELOPMENTS By K. FROST Esq.

Standard Telephones and Cables Ltd.

TH£ T. 6- R. IJC:U . ETIS, Xovembcr 19:!8.

COMMUNICATION RECEIVERS AND TRANSMITTERS

More and more samples of high performance, high quality instruments are coming into our stocks. Still the famous NATIONAL H.R.O. holds its own. with its two stages of R.F. Amplification. Plug-in Coils. Extended Wave Range from 30 Mc. to SO kc. Four models always in stock : Table : Rack and Panel : Battery : and Junior. Prices range for the Senior from £49 I Os. The Hallicr after s Extended Range, which now surpasses all others in scope. with the Sky Buddy at £9 9s. at the foot, and the most amazing Dual Diversity 2'1-Tube £150 model at the head. Perhaps the most popular is the Sky Challenger 11 at £15 (illustrated below). Employing one stage R.F .. definite image rejection, and wide wave range. This Challenger. the most popular general purpose model, EXCEPTING. OF COURSE. THE NOW FAMOUS SKY CHAMPION .... .

Eight Valves, Full Band Spread ... Wave Coverage 6.8 to 550 metres .... Monitor Speaker ... Separate B.F.O ... . AND PRICE ... £15 15s.

MORE SKY CHAMPIONS are in use in the British Isles than any other Communication Model. For the U.H.F. Man there is now the new HALLICRAFTER ULTRA .... employing the NEW R.C.A. 1851 Tube in the R.F. Stage : 1,600 kc. l.F. 's, and covering the range from 3.75 metres to 53 metres. To the best of our knowledge. t his is the only worth· while U.H,F. Superhet available at the moment. PRICE Complete, £52. H ALLICRAFTERS SKY BUDDY

'.!67

WEBB'S RANGE OF TRANSMITTERS includes the latest product of R.C.A. : The A.C.T.150 : 150 to 200 watts output on all bands from 28 to 1.7 Mc. : two 808's in the fina l ; Separate Pre-amplifier. In all. a superb instrument. Then the COLLINS 30J , which scarcely needs introduction. The range of N ATIONAL EXCITERS •.•.. MODULATORS ...•. A ND PRE-AMPLIFIERS A ND THE LATEST H ALLICRAFTERS MO DEL H .T. I. Full 75 watts Mod .. 120 watts C.W. Three wave-bands, switched. Complete. ready to put on the air at £73. Still the most popular small Complete Transmitter is the HARVEY U H X 10 <he <inr unll wllh van capabillues. 10 to 20 wuts output on ~II bands tro'm S to 160 metrci . Full~ modulated. Makes an ideal Orst TX or an E)(citcr ror the advanced amueur. C:ap:able or driving up HALLICRAFTERS SKY CHALLENGER II

THE HARVEY UHXIO

WEBB'S

to 250 wuu PA. PRICE or <he UHX 10, complete with Two.Band Opera<lon, lndud•n& coi ls lor two bands, £19. Powor Pack, £6 IOs. Shc·volt Gcncrnotor for Mobile Work. £9 16t. N ew Range or McELRO Y Mo .. e Aid s and Kay s. The l>les< McELROY Morse Code Recorder opor>lu direct from 21 watt ou tput from the receiver. Wiii take .speeds from 5 to l SO w. p.m. p,.lcc completo, £8. Tapo Pullor lor use with Recorder. £l 7s. 6d . McElroy Mors~ Tr.insmir.cer. - Convc ru the printed tapo Into lfnpulus. Used in con· junction with the TX or an Audio Oscillator, for transmhtln& at iny speed or for Morse pnctice. £8. This e quipment. with ~uxili~ry appar~tus, it available to accredited societies or groups on hire for pe,.iods of one month or mo,.e. McEl,.oy"s N e w Keys include the four Ll&ht Models - The Amateur at 6 /6 : The Commercial. 8 / 6 ; The Professional at ll /6 ; and the De Luxe at IS /•. The ever-popular MuSTRATE, wi th heavy cast bue. is still avaolable at 7 /6.

RADIO ~

(C. WEDD LTD.) I JJllDII N'C: IIAM D EPOT I

~I ('A llHS L AXE

14SOHOST.,OXFORDST., LONDON, W.l PI/ONE: CERRARD20$9

3

2GS TI-IE T . <!;. R. BULLE·Tl/I.·, :>:ovcmbcr 1938 .

. . ·~.·~Al· ~·.llltft ........... lr . . . 1,

\' \\',11 : • !I.

F7'ULFILLED At las t a British Amateur Radio Handbook. Written by many of the leading amateurs of Great Britain this new publication will prove of inestimable value to all who wis h to understand the theory and practice of Amateur Radio .

LIST OF CHAPTERS i. Amateur Radio. ii. Fundamentals. iii. Valves. iv. Receivers. v. Radio Transmitters. vi. Modulation and Keying. vii. Power Supply. viii. Audio Equipment. ix. Artificial Aerials. x. Aerials. xi. Prevention or Transmitter Interference. xii. Ultra High-Frequencies. Xlll. Ultra High-Freque ncy Equipment. xiv. Tele vision. xv. Frequency Measurements. xvi. Measuring Instruments. xvii. Station Planning. xviii. Operating a Station. xix. How to Become a Radio Amateur. xx. How to Obtain a Llcence. xxi. Great Circle Routes. x:xii. Selected References. xxiii. The R.S.G.B. and the Radio Amateur. xxiv. Useful Data, Cha.rts and Abacs.

24 CHAPTERS. Printed on good quality paper with stiff covers. Pages open fiat. Price 2/6 or post free 2/9. Overseas 3/6 post paid. r-------------------------------------------------,

I COUPON I I I I I I To the R.S.G.B. Sales Dept., 53, Victoria Street, LONDON, S.W.I. I I I

Please send me .. .......... (copies) or The Amateur Radio Handbook. I enclose P.O. for ... . . ........... . I I I I Name ..... . ............................ .. ....... ..... .. ................................................ . ...... .................... . I I I

Address ............. ... .... ....... .... ...... . ......... ....... ........................ ·································· ··· · · ···· USE BLOCK LETTERS

TI/Ii T. 6- R. BULLETJS, :-:Cl\cmber 1938. \!li9

Workshop Practice PART 1. SOLD ER ING

Hv "SHACK"

A GOOD soldered joint is the b:i~is of every piece of r:adio apparatus. When we pauso to cons1de'. the uumber of soldered joints in a

modem receiver and the slipshod way in which many amateurs make their joints. it is surprising that bad soldering does not cau~e more trouble. It only needs one bad joint to produce a fault which may take a week to IOC."\te. Further. it is not always possible to find a bad connection by m<:ans of a test meter since the joint may behave qu1to normally when an appreciable current is flowing yet its action under a minute R.F. current is that of a high, variable resistance. The moral, therefore, is to see that all solc.lercd joints are properly made in the first instance.

f<ac.lio is a good servant bul a very bad master. You C(Llt be per!cctly certain that when ever you dccic.lo to chance an item. be it a minor component. a doublful resistor or a poor soldcroo joint it will let you down. Tako no risks but do the job properlr the .first time.

The U se of Flux

We all know why a connection is ~ldcrcd but few c,·er pause to consider what happens during the process. Wben we solder we endeavour to produ~ a continuous metallic connection of very low resistance between the tag and the wire. \Ve want the solder to

even film over the hot metal. the thinner the solder flows the better the joint will be.

Solder and Resin

Solder is sold in various grades from a very coarse type containing about three parts of lead to one part of tin which is used for plumbing. to very tine blow-pipe solders containing one part of lead to four parts of tin. Fortunately the maker:. of electric soldering irons, which arc now in almost universal use. have produced a very satisfactory resi11 cored solc.lcr which should always bo used with these irons. In addition to the resin in the solder a small tin of resin should be kept handy on thu bench. Rcsm can be bought at most chemists' shops, but. only the best pale, straw coloured lump resin should bo purchased. Hofuso the powdered resin since it is often of inferior quality. A pound of resin costing about eightpence should last about a rear under normal amateur conditions.

Soldering H ints In order to proc.luce a good soldered joint certain

conditions must be ful1illed. . I. All parts to be soldered must be absolutely

clean. 2. !:>omc smtable Oux. preferably pure rcsm. must

be used to assist in cleaning a nd to prevent oxidisation of the parts lo be soldured.

3. All the parts lo form n microscop ically thin alloy with the two parts to be joined. Unf or tun ate l y all metals in common USO oxidiso rapidly when heated in

We 11111•1· pleasure i11 introducin.tr to our ret1tlcrs 11 new series o/ 111·/icles wliicli it is hoped will lim•c a wide appeal

Each 11rlirlr will deal with some spuijied aspect of Workshop PractiCt'.

bo soldered and the so l c.ler itself must be heated lo a temperature slightly higher t.han the melting point of

SHggestions for futm c m·ticles ill the series will br welcomed by the Author.

contact with the air and it is lo prevent oxidisation th..'\t a flu.."' is used which covers the joint to form an airtight seal under which the solder can flow. The flu..x also has another very important function to perform in assisting the cleaning process. All flu..xes arc slightly corrosive whon hot, some more so than others. Zinc chloride (" killed spirits ") is the best flux for most metals, but as it is very corrosive even whcn cold and difficult to remove it must be prohibited for a ll electrical work. Thero arc. of course. a number of proprietary fluxes sole.I whic!h arc excellent for radio joints. but the finished connection should be cleaned with a rag damped with methrlatcd spirits. By far the best and safcst flux is pure rosin although it is more difficult to use and needs greater care if dYy joints arc to be avoided. Resin being a solid at all nom1a l tempera lures and insoluble in water. is safe to use since there is no fear of tl1c flu..x causing corrosion l t is onlr a very mild cleaning a.gent when hot. therefore all parts to be soldered must be scraped scnipulously clean olhurwise the solder will not flow under the flu x. \.Vatch the blob of hot solder flowing off the iron . lf it forms like a globule of walor 011 a. greasy plate then the joint is not clean enough and must be scraped again. The solder should flow in a. thin

the solder. 4 The heat must be applied long enough for the

~lder to run into all Ute crc\'ice,; of the joint. 5. The solc.lcring iron must ha\"C the point pro

perly tinned in order to convey the heal from the iron to the joint.

G . • \ class of solder suitable for the job must be used.

7. The soldered joint must be kept perfectly still until the solder has had time to solidify.

8. All surplus flux, particularly if a paste or lluid. must bo caro{u lly removed when the joint is cold.

Clean ins

Tins sounds \"Cl)' simple. but. it is where most beginners go astrar. Cleaning does not mean polishing wiUt a. met.al polish, it means mechanically scraping ,,;th a proper scraper (it is not unknown for a beginner to try cleaning parts to be soldered with a metal polish 1). The most u.seful cleaning tool is a small three cornered scraper which can either be purchased from a tool dealer or made from a 4 in. dead smooth single endecl triangular saw file. Grind the teeth away for I ~ in. on all three sides until t he end forms a point. The grinc.l ing should be done on a wet grindstonu, finally finishing the edge~ off on an oil stone. Do not u::.c oJXCCs'li\"e prcssuro when grinding roward~ the point

3•

270

or the heat of grinding will draw UIC temper a,; indicated by the point going blue in colour. File~ are tempered to what is known as " de.'ld hard." since U1cy a rc required to cut all 0U1er metals: for the samu reason we n :quire our scraper to be dead hard. I f. in grinding, the temper is " drawn •· it will become soft and will require resharpening too often l ' ndcr no circumstances should a high speed carborundum type of wheel be used as it is almo;,t certain to !>Ollen the tool. Dcsides its use as a scraper this tool makes a good pricker for wood screws, the tapering triangular hole formed giving an cxcellenl start for the thread.

Tinnln1 the Iron A s<;>ldering iron ic; uc;cless until Ule point has

b<.-en unned becau'\C it i~ only through the tinning that the heat can be conveyed from the iron to the joint. The fi lm of oxidised coppc:r and dirt which inc, ·i tably forms on an unlinncd iron acts ;Ls a n efficient insul;Ltiou to the heat. To tin the iron, hea t it until it will ju-;t melt the ~older, fi le one face clean and before it has had time to d iscolour. rub it in a small heap of resin and bits of solder m a tin lid. Hepcat the process ";th the other fa.cc» of the iron till the point is comple tely covered with solder for about ~ in. up. Once a n iron has been properlr tinned it should hard ly ever need re tin· ning provided it is not overheated and resin is used <;xclu~ivcly as the flux The surplus resin which nnds 1tli way on to the bit burns. to form a black scale, which can be wiped off with .L cloth leaving a bright linnend surface underneath. An excellent war of tinning a ga~ or coal heated iron is to have a tin containing scraps of solder and salammoniac into which the hot iron is plunged This method should not be used indoors since the fumes are most ob1cctionable. also the iron mu;;t l>c nearh· red· hot so 1t is usclc!>S for an electric iron. \\"Ith the salammo1~iac method there is no need to clean the iron at all, just plunge the hot iron in lo the mixture a.nd the salammoniac will do the c leaning. Some of the P<Lste fluxes have the di.sad,·antane that the~· attack the !>Older on the iron mak1~t! frequcn't retinnmg essential but with resin, retmning should never ho necessary. F()rtunatcly electric irons arc usually 'old a lready tinned but the writer always prefer, to rct in the iron himself before using it.

Maklna a So ldered Joint

I .et 11 ~ now proceed to solder a so·called " 111111cd soldering tag " to a wire. If any a ttempt is made lo 111 nke use of l111s. so-called " t ir~ning" the ro~11~ 1 . is most likely to be a perfect sl!ec rrncn of a i i ry J O I n t I Treat llw tinning :is :L

dr~ty surface ancl scmpc it away unti l the meta l is lard b;i.re underneath. l l i~ not enough to produce a few s treaks of brass, scrape till the whole of the part to be soldered show" c lean hr;Lo;s. Pick up a.. small p1<;ce of solder 011 the iron, plunge it into the tm o! resrn and transfer the iron quickly to the soldering ta!(. The rosin will run down the tag followed hy a film of solder which should a.ppeM as though it want-; to mcel t11e bra-.s of the t:ai: . If ir bcha\'es l.ike a ~pot of water on a izrea.sy plate then the tag is not c lean . :\e,·cr touch a.nvthin" which ha~ just been cleaned for !><>ldcrin" as tJ1~ grease from th'? hand is quite enough to

0 pre,·cnt

the s<~lder runmng yroperly. ~ow ha ving cleaned and trrmed bot~ s rdcs of the soldering tag make the encl of the wire into a l>mall hook. put it through the hole m the t a~ and nip il up with a pair of

TH E T. 6- R. BUU.J:TIX, :\o ' '<'ntbcr 1938.

phers to make a mechamcal ioint l'ick up a small" piece of solder and some resm on the imn and transfer them quickly to the iomt .\fter the solder has run all through the JOinl hold the iron underneath to drain off th<.' surplus solder. 1 t is a.common fallacy to 11nagine thal the s treru;th of a soldered joint depends upon the .unount of solder used. It docs not. .\ good soldered joint "hould ha,-c the parts to be joined. 111 a' clo'-1: a contact a' pos5ibl.: wit h ju;;r Mr1trc1cnl :;older ldl to pre,·ent them moving. That 1s why it 1-, alw.1y:; best to make a mechanical joint lir,,t. Currously enough, although the tinning on manr components is often of a ,·cry doubtfu l quality, tinned copper wire takes solder readily without much cleanim;. It is a.; well to pull the wire throu!,!h a clean 1,;loth to remO\'c the surfai:e dirt and str.ughtl!n the wire. If the \drc is \ 'c ry old or dirty then pull it through a piece of emery cloth or glass paper.

A ,·cry common method of soldering- is to lay the wire· on top of the tag (unclcancd of course), smear thl•m both with llux. drop a large blob or solder on with the iron and wan until it stick:-.. This clas~ of joint i:cts t.'Xactl~· wh;1t it descn·es troublc at a \'Cry <·:1rh· datl' . \ hght jerk woulcl pull t ho jo int apart, for tlu.: sold(:r has no t been g iven a fair chance tO adhere to ei ther lhc tag or the "irt·. The foundation of nil good .oldered JOllH'> 'hould be a i-ouncl mcchanrcal Joint as ;~ beginnin~.

:'\ow go away ancl -older up that frequency motor properly 1

Photographing A mateur-Built Radio A pparatus

On,• of our contributor-< h;1,. forwarded a qucstionnair~ '<'eking informatron n•g,1rd1ng the be,.t methods to employ for photographing amal<.'ur-built radio apparatus. !n vil'w of t he fact that many other-; may be intcn·,h•d, we invite atry member \\;t h ,•xpert knowl<.'dgt• of the ... uhjccl to furnish us ";th a short arttrlt• fur puhlil.ltron. \\"c shall be glad to for ward a W(l\0 of the ahow··mt•ntioned questionnaire to anyorw able to al>.,rst.

Isle of Man Radi o Society ~lr. Lawsen, the li on Secretary of the abo\e

Society, rnfornL~ us that they ha\'t.' ju:.t complett.'d the construction of a :1-\'al\'C T ({ F. recch·er for us!' by the· Club.

On Ot•tober 27 a vi:.rt wa$ paid lo the Dougla, Corporation Power s ta.lion hy kind 1wr111bsion of tlw Borough l ~ngineer. On Novcmhl'r 8 tl series of lilms loanc<J by tlw 11.T .Jf . Co111f>1111y were cli"playccl .

~lorsc classc~ ha\'C lx:en arrangt•d. and 1t 1s hnpccl t hat at any early date lh<' Society \\Ill obtain rt-. own tran,mitting licence.

W7BJS \\"e ar,· informed ll\· GUB\\" ihal \\"iBJS of

\\.yoming i .. anxious for G contac.:t :. on the 28 ~le. band. I-It• normalh· works tclephonr on 29420 kc.

Reports W anted G3LT (Bungay. ~ur£olk) on hi, 7 a nd 14 )le.

C. \\" . and 'phone tran,mi-.sions. All reports will be ackno\\Je<lg<.'d.

TI/£ T. 6- R. BULLETJ.\' , .::\ovcmbcr 1938. 271

A 56 Mc. Driver Panel By W. 1~. llo1.r.0RI), .\I.A. (C:5XG)

IX c.onsidcring the clc~ign of a 5G .\le. Drive, Panel the first consideration was, of courser ' tnbi lity, buL the second was rqunlly important,

11a1111:ly, cutting dO\l'll interstage losses a ud matching up tlll' load.

It wa:. considered nccc:.sary lo hav(.' one complete p.1nd to gi,·c a 56 .\le. output, \\hich could be used for portable or emergency work, and which would hl· capable equally of driving a pu~h-pull output -.1.111<· without alteration.

Oscill:u:or

l·or the CO a 6F6 very hcanh· b1a~cd '""' cho~cn. Tlw cl rive from this is su ft1tw1it for mo~t sensiti\·c tl't roclcs used in doubling, ancl the a nod1::1ud c rys tal l'11rrent can be kept very low. Jf a Tritcl is u"cd, ny~tal current is unnccessari lr hi;:-h and the extra adjustment is a temptation lo ")llCC?.c a hlth: mon: out, in ,;pite of the fact tha1 tl'trodci. do not like to hl· ovcrdrh·en, when both quality and stabi li ty ~u ller.

A fundamental oscillator, \\ 1th a good choke, is lhcreforc usl'CI. but the cn~tal mu~t be one that i-t,1rt' casih-. l 'nder thc,i· rnnditions .mode and cryst.1) Clll"Tcllt llC\'Cr ri~<'

H~rmonics

T he11: b il snag of course ; there always is when things a ppear so hl·;wt ifully s imple, and tht" (iF6 output is very good. Unfortun:ttely, thc odd harmo111c comel. through nearly as strongly and much more c:isily than the even. and a good deal of trouhlt· was cxpcncnccd 111 adjusting tht• load so th;ll power was not wasted in putting oul a n unwanH·d "ignal on 42 Mc. The 807 would put 300 mA into 100 ohms at this frequency wuhout all\· dtort at all

'rhl· la11,c wa~ th•· O\'erlappmg ftt'lc.ls of the coils, and till' t.ic.t that lx>th t etrodes require an amazingly sma ll amount of drive. Fame.lay scrct•ns, as dcscrihl·cl in t he i\la\·, 1938. issue obvialt•d unwanted coupling. :11\cl a n cwning's hard work found tlu: best. working ratio for the transrormers.

Coils Sinn· thb i,., a 0111· band tran~mitler, all HF leads

a rc ahov<· ancl all others below t IH! panel. l'orccJain insulator~ Jl ins. apart give rigidity and cnabk n·ally low lo,, trdnsfomwrs to be a1rsJlaLL'<i.

•"- doubling •~ c.irncd out at l'.1ch anodl'. ,,,1vcr plated tu1wd pmnari1·,, arc U>t·cl. the wirl !icing

Circuit of S6 Mc. Drivu Unit. Rl. RZ.

RJ, R6, R4. RS, CH.

SO.OOO ohm•, 20 watt Pumiu. 2,000

20.000 s.ooo

ISO.OOO ., 2 : I choke.

Couplln1t

'frl rodes, especially low capacity ont•s , arc Yery s lls<'t•ptible to the effects of the re lleclcd load . Tram.former coupling was tlwrdorc dccidrd upon. C:apal'ity coupling is unncces'><!rily expcn-.h·e, gi,·es ri~e to a\'oidablc losses, but " ~implc to install. Thr fact that mica conden~t·r lo,ses arc quite higb at th is frequency w:is also a dvciding factor in the choice of coupling. It is well \\Orth while taking the trouble to suit the transformer lo the \'ah·e, and cheap but difficult to find the tx: .. t loading conditions.

Frequency Doubllnr

A valve jus t large enough for the drive, with this very d licient coupling, is thv GL6 a nd Lhe same argunwnt applies to U1c second F.D., au 807, link coupled to the aerial or push-pull amplifier; inp ut to t11t· 807 being 5 to 40 watts , without a lteration cxct•pt fixed bias.

Cl, 2. 4 CJ. s. 6 C7. 8 C9, CIO. Cll.

.OJ ;J.F . T.C.C. t ype M. .001 .. .0015 .. .. .. 5.p fnte. neorb, all in. 3-11/tite, hall in, Joubfe spaced. 2.p/ate, neutraU1ing s paced t in. Ray n1art

Ceramic.

~o. IU w111ge copper wi re, and lht• diamclc1 J in. This win: ca n be obtained in short lengths from loca l e lectric ians, who use it for varthing. A. 4 volt battery. a s ilver coin for an anode, anc.I fh·c minutes in :i i-olution of ;.il\'cr cyanide (made from rat poison wluch can be obtained from any chemist) will add appreciably to the looks and possibly to the etliC1l'11er of the coi ls.

An apcriodic grid coil surrounding the anode coil seemed the obviou-. way to accommodate the greater inductanct• nt'cessary. and 18 gauge enamelled wire (coils or l i ms. diameter) was found to be sulhc1cnUy heavy to "stay put" while tbc grid coi l was being f1tlccl into place lo give a tin. all round c learance. This thicl<ness is rigid enough. easy to work, and makes a H·ally good mechanical job.

It is well t.o remember that the lowering of inductance due to the proximjty or the grid coil is appreciahlc a t these frequencies, :ind the primary

27'2

alone should reson:nc with the condensers practically all out.

The <W6 will only ~tand the loading of 5 turns over the cold end of the primary ; the 6L6 doubling to 28 :\le. enabled much closer coupling to be used, eight turns co,·ering t he length of the primary winding \\"ith this ad1ustml'nl the reflected load is c,·en throughout on keying (meters dipping equallr). and this panel can he run from a single 250 volt pack \\ith condenser input and give a T9 nott-. Yet with choke input and 600 volb final, the 807 can be run up to the full rating of over 40 \\atl,.,

Screenins

To get a sufficient :.eparation of input and output, and to avoid having to announce that " reports o f n:ceplion will be welcomed for this band only," the 807 was mounted horizontally. Leads arc very short and the single Faraday screen pre\'ents coupling between coib and condensers.

A good deal of thought was spent on the mounting of t his va lve. ll seemed a waste of lime taking the trouble to do away with iron and masses of metal and t hen uN<.: a metal bracket ; ~o i in. celluloid was cut and clipped on to the base with two ~mall aluminium angle pieces, pinned through, !>O thal no fixing shows above the baseboard. This adds greatly lo t he appearance and possibly lo the enicicncy.

Thi.) base, I 7 in~. hy 9 ins .. i" of hand polished i in tive-ply, stained mahogany 111 this case, backed with th111 copper foil. This O\'crcomes many earthing problems, and all by-p;i,, condensen; are soldered directly from the socket wire to the copper sheet.

M eterina

\lo,cd circuit jacks, insulated on :-mall piece,. of ebomte. arc scrcwt-<l to the front l'<lge for oscillator anode. F.D. anode, t·athode of final for keying or cathode modulat1011, grid of 807 for fixed bias (thrct• and a half times cul-ofi i~ 11sed), and :inode of $07 for metering or modulation.

Modulation

Cathodt: injection for modulation has SC\'cral advantages. :\om1allr using CW and its appropriate bias, it is convenient to change stra ight over by plugging in a 1- 1 output transformer in the cathode, when the hias automatically adjusts itself for tht• new conditions.

Cathode keying h;h so far given no in terference with powers up to 20 watts on the same line as the BCL set with t he usua l simph: :filter on t hu key itself.

For this power two i.mall tetrodes in push-pull, using Fe1•ra11ti stock transformers, enable a good enough match for all general purposes without the expense of special modulation transformcn; for which a very special price is asked at present !

I lead amplifiers, loo, arc a nuisance a nd unneces<,ary. lt is pos:.iblc lo have a high-mu triode. mixer, low-mu triode, and tetrodcs or pentodes in push-pull, with till' power oupply and necessary control' on a similar 17 ins. by 9 ins. chassis. Sufficient gain and power arc available to run three speaker~ from microphones usccl for rebroadcasting speech in sepa'ratc rooms. Although under these conditions. hum is noticeable, 1t is negligible when modulating the tran,miucr, a,, tested at half a mile on a supcrhel itiving loud-'JlCaker \'Olume.

1'll£ T. & U. fJUf.LfiTf,\', ~o,·ember 19:18

C.trdul la,·out and a sen'1hk· lht' or "crcem·d cable enable,, the microphone to lw uwd c\•en up to 100 feet from the ;imphtier.

O utput Prec~utlons

Fur use on ''<•ry low power, regeneration in the 807 1:. easily oht.11ned by inadequate by-passing (.(){IO I instead of .llO l5) and gi,·e, about JO per cent. incrt>ase in output. This, howc,·t•r, like the Tritet adjustment whu;h affects both stability and note, makes a T9 note diflicult but possible to attain. .But even then ;i i;ood TS is <1lways given, and the slight extra range may on occasions be worth whil.c.

A fair amount of time was spent at hr:.t m endca\'ouring to gang two small receiving condensers do11blt· spaced for use as a st•ries gap and as a split stator. Xo nwchanical dillicultics were encountered in matching up, or in making a rigid job, but there was far too much metal for efficiency and the brass bracket formed n closed loop. One of the circular plate neutralising rnn<knscrs clocs ,·ery well.

Pe rformance On seven walls input to the fina l (C.O. 12 mA,

F.D. 15 mA. F. D. 30 111;\ ), the hcam• has given a consistent SS signal at twenty miles over a fort night':. straight nm (including the full moon).

ll remain~ to be occn \\hat it will do on full input, but oplimbm is as strong now as in prewircless "angling " days, and perhaps it may yet be legally pos,ibk to tr~· it out as a driver for a pair of HF 10(),

Interference Xo trouble h,i,., C\'cr bc.:en experienced from

ke\'iog intcrfer<'nle, and thi' is regarded a, being due to the following precautions:-

{ I ).\ maim. hlter, consisting of 16 s.w.g. D.C.C. wire (wound a,, a <>hell -I ms. diameter) and a . I . I µF londcn-;er to t•arth ha., alway" been a pc.:rmancnl lll'>tallation on the radio line.

(2) Low resistance copper screening enables short direct connections for decoupling, and no earth is u~l'd on the tran:,mittcr.

!J) Twenty watt resi,,tors from Prei111rr Supply Stores arc no more expensi\'e than graded I to H watt l}'Pl'' as usually specified. They run stone cold , a nd, owing lo t heir ~ i zc (abou t -I ins. x ~ in.) act as useful chokes.

,,.,. 1'. & R. BuL1111s, Soptt111ber, 1113•.

Sussex Short W ave and T elevisian Club A ctiviti es

On September '27 at Tho Pavi lion, Dognor Regis, l. lr. E. J. Willia ms, D.Sc. (G2XC) savo a very instructi,·e lecture on l\lagnctic Storms and Sunspots and thei r rclallonship to radio conditions.

The club's annual outing took place on October I 2, when 30 members and friends journcd by coach to the Murphy Radio Co.. Wclwrn. After an extensive tour ol the factory. a lecture and demonstration of telc\'bion was gi\'en, followed by a talk on ultra-short wave dc,,ii::n problems. Se~·eral R.S.G.B. members who arc.: e mployee:. of t he Murph\' Co .. joined the party for lunch.

On October 27, ~lr. I'. G. A. Voigt lectured on high quality n'production.

)lcmbership particulars can be obtained from the jomt Hon. Secretary. :\lr C J. Rockall, G2Z\', " Aubretia," Sea held Roacl. Hustington, Sussex.

TI/£ T. 6- R. BULLET/.\", );o\·emh<'r 1938. '.!73

Automatic Change-over System for Break-in Operation.

100%

By H. C. l'Ac~ (GG I'.\ )

This arlirle should prove of particular i11terest to members of the Cfri/ia11 Wireless R escr1·c wlao are faced w11/i the pro/l/rm oj operating their s/11lio11s w11la "break-i11" co11ditio11s.

FOR some year:> the wn1t·r ha-; IX'en in lhc habit of working " Ureak-in " when using C.\Y. \\"ith the coming of the C.\\".H. and

the necessity Cor operatin~ a rnce1vcr on exactly the ~ml' frnquency as the transmitter. 1t -.oon became apparent that an impro\·ed ;,y~L<~m of control was essential.

The most general system in use to-day is to run the rcceiYcr on a separate aerial and key the first stage of the transmitter. so that no spacing wave i:. present when the key is up. This sy!ttem works fairly well when the receiver and tran-.mitter arc not too close to one anot he r in frequency, bu t when they coinc ide the key thumps arc terrific, and no self-respecting receiver will put up with sucb treatment for long. Apart from this fact, the strain on the cars is too great for contmual operat ion. wlubt the system itself ::;:l\011 rs too much of the "i:ood old days."

General Con1ideration

:\ow if the rccei\·er can be rcmkred inopcrati,·e when the key 1s depressed we have the basis of a system which is very much better from all poinb of view. Althoui:h the method employed by t he writer is simple, there arc one or l\\ O points which it may be helpful to discuK'-.

The first and most necess;iry ret1tnrc111ent is lhat no clicks of appreciable !>trr111it h sha ll Ix· generated. l{cfcrcncc to the diagram shows that the basic ci rcuit cons ists of a chani:c::-o,·er relay which cuts the H.T. off the recen·cr il'- --0011 as the key is depressed, and \"ery shortly aflerwarcb doses the keying circuit o{ Lhe tran:.nuucr. \\"Jule this could be elTecLed by a single relay fitted with multiple con· tac ls it has proved more satisfactory in practice to use a i.econd relay for the actual keyini: of the transnuttcr . The need for very l11gh in~ulation of the relay contac ts is thus ob,·iatccl.

Study of the c ircuit arrangcm1ents shows that when No. I re lay breaks the I J.T. supply to thu receiver and c loses the cncri.:is ing ci rcuit of re lay ~o. 2, the keyin!{ ci rcuit o f the transmitter is closed \\"l11le this only takes a few m1lli-scconcls , the laf! m the closing of Relay ~o. 2 1s ju~t ,..u0ic1cnt to allow the receiver to go quite " dead." This take;; a short while owing to the click filter in the recci\·er H .T . + lead. T his filter ' lops all clicks which may have pa.s:.ccl the filter .11 the relay contact~. Lim-; en,uring noiseless keying

Cli~k Filters

The rccei\·er click filter can cons i' t o f a small I.. F. l·hoke and condenser o{ a \·aluc winch must be such that the recei\·er <loci. not remain energised too long. This of course depends 0 11 the li.T. drawn by the recei \'er, but probably mos t set~ will be well served with a value of 1.0 µFor less.

The dick filter" connected directly across the relay contacts. a nd across the key itself may have \·alues of. I µ.F and -100 ohms. Condensers of a mple ratini: ~hould be used but the resistances can be of the half-watt \·aricty, the except ion to this bcini: the filter across the key ci rcuit. where a resistance of higher rating is advisable, depending on tho power to be keyed.

Mosl operators prefer to monitor their C. W . s ignals all the time they arc =-ending. and to enable this to he done without switching the output of the monitor may be fed tiia a tra1isformer to tho 'phone termin:ils of t he receiver. lf this method is adopted it will probably be necessary to include a filter c ircuit in the 11 T. + circuit o f the monitor to elimina te any remaining clicks, if the 11.T. supply of the momtor is not !>elf-contained. This filler is con· nected m the same ITh"\nner as that for the recei \·er, but a resistance of 25,000 ohms may be sub,tituted for the choke. The condenser should ha\·e a value of 1.0 IJ.F.

••

Circuit o f Automot1'c Chonge·oucr Sys te m for Break·in Operotion.

Re lays

The relays employed arc qu1~e m~xpcnsi\"c. R ehn- ~o. I i> an old P.O. upnght s111gle-pole change-over instrument which can be purchased ~or a shillinl{ o r two minus contacts. Contact:; o f w~1te metal or sil\·er can be soldered in place very easily. A 3-111. length of "hitc metal wi~ of aboul );o. 16 gauge can be obtamed from most ieweller.; for a1:>out threepence. This relay requires an encrg1s1.nl{ volt.ago of about s ix volts . which c.an. be supphccl from a sma ll dry battery as the dram 1s !'llla ll.. Rcl;~y No. 2 is a more modern P.O. rclar w~th. a

resistance of 7.000 ohms., winch also 1s quite inexprn~ive. The energising voltage is of the order of 60 \'Olis, and as the current consumption is only

( Co11ti1111ed 011 p11ge 3 16)

'.!74 THE 1'. 6- R. IJUU.P.TJN. J\ovember 19:1$.

The 1938 "C.W . 56 Mc. Trophy" Contest By J. ~- \\'.\l. KJ:R (G5J l:)

AS much 111f111111atio11 •" po~sibll• has been purposely 111cludecl in th.: accompanying table (whith sets out in order the com

petitor.. in thb }'<'ar·, G.\\' 51i )le. Trophy Contest ) bccau:.c to do full JU,,tic1: to the cntrie,, anrl reports sent 111 would occupy much more ~pact• than the Editor would ft•t•I justified in allocating to this "write-up." /\swill be M'Cll , the number of entries received is cons iderably gn·all'r than las t year but, as appears to bt· a common trend wherc contest s are nmccrnecl, vc•ry manr more were acti \·e but dirl not send in 1·1lher enl ri1·" or reports. A census was takc11, . o n the line" of lhc J:land Occupancy Checks , wlu ch s lli>Wt•d t hat as 111a ny as e ighty-six tr:rnsmiUing s tations, s itual\•d in Great Britain and Ireland, were ht'ard. CJnc or two Belgian s ta tions \\ere aho reporll'cl. whilst it lb e vident that man\' recciv111go ~tation~ were active· during the period of the con tc~l.

In view of th is, it is somt•what o f a mys terv why mon· clid not report. It it< prohahle that ' mam· had negative n·~ults wh1l,,t a11othcr JlO''ible reason, sugge'>led by (;(i(;R, i-. that. in the c:be of those silu,1ied in the populous centres. such as London, it \\:ts not. consic lcred wort h whi le reporting unle~s fresh ;,tat1ons hacl bc<'n lward or worked. The writ('r would likt• to point out that tho'e member"' li\111g in the pro,·mce, aH· anxiou' to obtain information on how their fl'lh>" 56 :\le <·nthusia.~t" in large towns and otht•r parts of tl1t• country art· faring and particularly what dbtanccs art: covered regularly from fixed QHA', Often, undl•r District ~ott•s, one 'cc" that "°-and-,o worked -.o-and-so on 5G :\le .• but the mileage 1s \ 'Cr y rar1·h· stated. 111c 'ending Ill of 1eports Ill a contest such a,; tht• on<: for the G. W. Trophy, whl·n activil\· ma\· bt· cousidt·n·d to n·ach a peak, wtiuld enabl~· informaticm to be corn·latccl, lo the ht·ncfit of a ll interested.

The Leaden

Aft('r the foregoing mild <'hiding. we l11rn to tlw slal1ons which nppcar at tlw top o f the tab!<-. H earty co11gr;it11lations wi ll he offrn·cl )), · a ll to Daviu ) 'litclwll nnd hi ;, partner, )I. C. (' rowlc\':\lilling, joinl opcrato~ of l; \\'6A:\I '. for their ach1t•vcment in obtaining M1ch a Iargt: hWre, whjch wo11 lcl have been over t he 700 mark if t he ~on tact with G5:\'11 .. 117 miks :lway. had taken plact' he fore tlw clO.~•· o f the cont..sl instcnd of 25 minu l<·s afterwards. T ht• •·ncrgy ancl enthusiasm which thc.~c two meml><:rs have di,playcd-wltnc,,s tlwir \'igil on ihl' Is h: of )Ian la-.t year make their success well de,,(•rvcd.

(i. I le nderso11 , C:t!J VI'. who liuishecl St'tontl, ha!. concentrated on 56 )le. propagation and has obtained con-.i-.tenth· l(ood result,,, \\'hilst the num~r of poinh he obta11wd is much less than that o f the \\lllllt'~. hb pl·rformance \\a,, a ven· fine one. ·

Austin Forsyth, G6FO, i,, a notht•r well-known 56 :\le. worker and his performance is outstanding because he wa-. operating from his home QR.A, at a low le\·el abo\·c :.ea. I it' abo was unfortunate in that the contact-. macle with G5RD and G6X.\l

on tht• Friday evt:mni: \\ere not n·11t·atcd dunni.; the period o f lhe conte,,l.

lt is a notic('ablt· ft•:\l11rc that practiralh· all entrants heard man\' -iaticm,, ''hich tlwy \\ere: unable 10 contact <:HFO and C:8j \ ' ht•arcl l'ach other's ,1i:nals ancl \\l'rt' unlm' k\ not to <]SO.

lndlvldu3f Station Oucr iptlons and Resulu

The cquipmrni t• mployecl h y (; \\'6;\ /\ ~ > \\'a:, exte nsh•c, and riRhtly !-0, for wh1•11 one di:c:icle,, to conduct cxpcrimenb fr om a si te out of the ordiuary. it is well to mak1' cvcrr JXh.,1hl1· preparation in orde r to find out j us t ":hat m n be accompli"lu;rl w ith cliffu rcnt tr:111:<111iltc rs . rt't'e ivers a nd aeri<t l systems. I t is u n<lt·rs tnocl t hat the opera tors have wri tten a full acro1111t of the .. tation. it:1 equipment and results, so liitlt• will b~· ,,aicl here. To quote Davitl i\litchcll '.; O\\ n \\Ords, " the lcsb provided splendid proo f of l ht· s uJH:riurity of c rysta l-cont rollcrl C,W . transm i,;sion" in conjunction with stra ight and su1wrllt't n:ceivcr,., for Jonl{-c listance 56 )le. communication." llis 'tation's extremely high ,.core can be auribult-d to the high :werage disrann•s co\·ered, it heing notable that, 0 111 of 26 conrarts. onlv six '"'rt' under 50 miles, whi lst four (or, iucludi ng G5i\ll., five) 1·Xt1·cdcd 100 miles. Station-. heard hut not co1llactt·cl included ( ;(>Ll (;\lan,tit•l<I. 122 milt•sl and (;(i(;O (Hui:ll\', 130 miles). C. \\". si~1lilb from G\\'(iAAI' were heard by G60T (London, 208 mile;,) ancl GGX~ l' (Luton, 178 miles). and many report.. wt·n· rccc1ncl from stations over 100 miles a\\il\'. The Joni: , .;,,ual range from 1 he M1111n11l of ::ino\\(11111 1" an important factor. hut the usl' of modt•rn .1pparatus al'll <.Onlributed largely lO thl good n•sult,, obtai1ll'd, lhc"e showing an improvt•1111·ni O\'er prt•\·ious cx1w1htions.

The success of CSJ \' I' can ah,o be attribu ted to the employment of mmlern equipment. J Ji , trarn;mit l er consisted of a single t w1n-triodt: valvt•-an RI,.~14-u~ed a ... a CO FD. with a 28 )le. crntal. .\loclulation was eftcclt•cl, when required, by 1i1eans of a HL<i, prccctled by n (i('5 : a ~mall g .. ucr:i to r supplying t he anocl1• voltagt· :mpplits. The r1•cci,·er consi,,kcl of a 9;;.1 (Arnrn 1\•nioclt• ) RF. ;11nplilier, iollo\1,•d ))\· a fll\7 ddt·cior, .1 rnmbination which. as G8J V ~ays, prnhahh· rakt•,, some beating. The " ·holi: formed a rnmpat:l a nd thoroughly up-lo-date sta tion. wh ilst Lhe results vouch for its dlic ieucy. Snowdon was Ow most distant !<tation contacted (90 miles) and the good number of QSO's (many o,·er d1,.tancc" cxn·1·cli11g 50 mile,,) built up the :.core. Signals, all C.\\'. were rt•1·1•1wtl from C60T (T.ontlon), C6FO (,il;'cwport. ,\Jon) and G5 Ji.; (Bristo l) a t an avt•ragt• strength of JH.

ThC' log and report submitted by GGFO were mo:.t complete anti make mo,1 inter~ting reacling but ,,pace prevenh more 1ha11 a brief outhnc of the contents being gi \·cn. The tran ... mittcr employed three vain·~ an .\ 1'1'-lg trikt with a 7 )le. c rys tal. anotlwr ,\ PP-lg quadrupling to 56 )le. and an JU,.3-1 pu-.h-pull J)O\\Cr amplifier, taking an input of 2-1 watts on a frcqm·ncy of 57.4 'O kc. The r.:cei\'Cr w:i.. a -.tr:ught t\\O·\·ah'e, with a l/u;a& D.21US\\' as detector. Detaib of the DX contact::.

THE T. '-"' H. BULLETIN, :\ovember 1938.

made by CllFO during lh<' J><•riod of the contest, an<l before, appeared in J; .... t month's Bn.Ll!TIX

and it will be n·called thal llvl' w1·rc O\'er distances exceeding I 00 miles. Thl• OSO 'dth G31 I\\' (Tcignmouth) " al"° notl'\\Orth\· ;" the latter wa-.. only using 4 w;iu,, from 0.1t11•ric·s to co,·er the 76 mile.-.. C. \\'. "a" u,,ed l'XClu-.iv1•I\' and numerous reports of n•c1•ption owr Jong distances indicakd that lhe sii:nab w<'rc bei ng radi:ll1•d in all directions, except to lhe north-west. This wa~ probably due to the mountainous ma-. ... e-.. nf l\orth and Central \\'alt-s and was unfortunat1: 111 ''il'\\ of the numlx•r of s tation-. ;\cti"" 111 that direction.

G5ZTP. who '"h as.-.istccl ll\· GS~LD. G3P J and '.!FF);, 1i-1·d the ,.ame ap1)aratus-a batteryopcrated tra 11-..cei\'er-as J;L' l r<•a r and a lso lilt'

275

to that w .. etl by G6 1'0. Thi· J11gh spots were the contacts "i t h (;{; \ ' F and C:HFO, but the score would ha,·c b1.•1·n much largl'r 1f mnn• of the nearer stations had been active.

Opt~ration ... ac GS.\..\ P \\t'r<· not commenced until noon on the Sunda\·, in \'ll'\\' of which the :.core is a rC'markahly good ont·. It "iU be notict•d lhat the numlx·r nf qso·, obtai1wd was second only to G\\ '(),\i\ I' (C'.!OA's en try. it ' hould be mentioned. was n·cci\'cd loo late to lw olliciall\' included: but most of tll<' contacts ''<'rt• over short lo medium distance-.. Tlw <'quipmcnt was \'Cry similar to that employcd by G\\'fiOl-\P

El8L ll'<'d a battery-opc·ratcd transcci\'cr and had only two contacts, lh t·'<' being with E 12J and G\Vf>Af\ l ', hul the ~•rl·ng t h of s ignals each way

0 1wmi OF i\!EHIT

l'o>i- C.111. ( ! 1\ 1\ J>oinb. I Cnn-11on. __ I

I '~I

1:\\'tl.\.\I ' Snl)wdon ()58 '.!Ii

'.!

I c:H.J \ ' I' J\ r. I .cl'k, Staffs I 41) JO

:i (;f;F() :\..,wpo rf , ;\Ion. 1:rn 5 -l c:.~ZTI' 10 null•s Xorth JI:! ~

or l'r<·,ton 5 <;\\'HO I\ I' :\r Q,\\C-,try 109 s G C::!XC Port ,111011 t h 106 ()

7 c;s ' \l' B1rlwnhead ill I'.!

8 E ISI. Hock ;\lountain GO " 9 c;S \l<!I' l.lani:amma reh 5~ '.!

\\'cJJ,, Bree. I ll C:lll\' ;\lanctw,tcr -15 5

10 l C:'.!\\'SJ I Lon:: ;\lynd. 45 :1

lO c: urrs Sal op

;\Journe i\I bi. 45 I 1:1 CHVF Bristol ·II :1 1-l C: \\'5Fl 'I' Presta tyn )lln. :J7 5 15 c:iJ " London. S \\'. 17 15 i

16 Bristol 6 '.! 16 )lorthflcct. l\enl 6 2 18 CH I.\' Winchester 2 I 1 rn1~

C20A Wallascy 13

~ame s ite. l l i,.. evident that l'.1rlini; Pike is a good location a nd from it the ~1i; nals are :.prayed in a wide arc to till' -.Olllh, covering most stations within an a rea of GO mile-.. or so. In t hi~ case, a ll s talions heard, wi th but on<' except ion (G5KL), \\'Crc contact.cd.

( ;\\'GO l\ I ' Sl't up his s lation m'a r Oswestry a nd was most "11 c~es~ful in worki ng s ta tion;; to tlw north and north-west, on!\' (;5 )1 L being heard to the south, '' ith no contact lx.·ing effected. Tht• 1ran,,mittcr ,,,1, a 'Clf-<'XC1t1•<I l lltra-Audion and two recl•ivt•r,.. w{'rC employed. one ,,;th and one ,,;1hout "llJll'r-regencration A number of ,,tation,., u-;i ng C.\\'. ''ere heard on the latter.

The mo"t 'outherly ,,lallon taking pad w:L-; G2XC, who operated from hb home QRA with a crystal-controlh:d tr.i.nsmittcr, employing aTZ05 20 as a final J>ow1.•r doubler, the rc<eh·cr being ,,imiJar

~~pt• Ot I Jn- H t. F .\ !'rial(,) I r.111,. put.

1

a. or 11111 tl·r. watts '-Ca I'.

\ 'ariou' l' Olllhllla· c .l' arHI 10 35(j(l I' tion, . ~.(',

Vertical !·\\'a \'t' (',(', 8 ) ()()() I' Long IO X ~ ·ll':t\'C l ' .l' '.!4 '.!00? F Lon~ S x a ·\\·a\'(' .... c. . ~ l.S I :17.'i J•

\ 'ariou ... ... ,., 8 I' Lon~ :{ v ~ -\\··· \'(._• I ' l :10 F

Zepp Vertical &·w.1\'t.: ..... !) I'

Zepp. Vertical !·wa' ,. and .... (' I! 900 J•

reflector \'erlical !·\\a"" eh· ... l' JO 60()> ,.

pole \ 'enical 2· !·\\il\'C

' l 10 WO I·

in phil'<' \'ariou:- l' \.' u H Hl9f> I'

s t'. r \ 'ariou.., I< 10 :JOO F \ "ertical !·w:L\·c l l I II 81)0 I' !-wa\·t.• :~ml re- l c 10 F

llcctor \ "arious C.(; :m :150 F 1-wa"c \\'andom (' \ 0, 5 F

C.C. 1(1 F 14 :'l l c. tlouhkt 1·.c. H.5 r

in l>oth ea-..,.,., was ::i9. G20A was heard at good st rength.

His report docs not ... ay so, hut for G5)l(l, o f Li,·erµoo l, to ha\'c bc>cn ;i,, far south as Llangammarch \Vt• ll s, one would imagine he must have been 011 holiday. The cquipm<·nt in his case consisl.t'<I of a GJ.Ci conncclt'<I as a t riodc oscillator and modulat«d h\' another ()J.H. whils t the two-valve recei"l'r t'011ld be opcrall'd :i- " straight " <H .. quench" .It will. 13oth <2SO'" were with s talion" ~itualed to the uorth. and al though G5~1<1 am! G6FO wt•n· only 'eparatcd h\' 30 miles, neither beard a 1 r.11;" of th<' o ther

T he tra1hmittt•r at t ::JB\' ,,,1-, a multi-stai:c one with a type :17 ,·ah ·u as a power amplifier. the recci,·er Uclll!{ a ()J-\7 H. F .-111 .'.! lo\ - l'cn. com b111at ion. .-\ numh<•r of mtcrc;tm~ :wnal tc~ls were earned out on C \\'. '' 11h mo,,t of the -.tations worked.

2i6

G2WSP clcc•idcd that lhe Long l\lynd should bt: a good spot for portable work hut was disappointed lo find, whi:n he arrh·ed there, that it was not possible to reach the top and the station had to be set up in a dip of lhe hills. Thh probably explains the rather poor results obtained GS:\lL, GSB:\l and others \\Crc heard but not worked. The t ransmitter employed two \'a h-es in an ECO/ P,\ ci rcuit and the two-\•al\'C rccci,·er incorporated optional quench.

GISTS's only contact was with G\\"6A..\P, 115 miles away. :\o other details a rc a"ailable but the spirit behmd his remark that " I want to show there is some enthusiasm on the 56 :\le. band in Cl "is to be commended.

G6\.F, a keen C.\\'. enthusiast, used his ordinary equipment. al home, the transmitter being crystal controlled with :\ T20 in t he linal stage and t he recci,·cr :1 sl raight two-valve. lie heard several weak telephony signals anrl was unlucky not to obtain more contac ts.

The three-v:1h·e c.c. transmitter used by G\\'SFU P could only be modulated to a low degree and the fact that the resulting signal would be difficult lo decipher on nny receiver al ;L distance, probably accounts ror his hearing many more stations than he was able to contact.

The sole entry from the l.onclon area was that sent in by G2J I<. who worked M:\'Cll stations, the furthest being G2 UJP. 32 miles away. :\lany more. mcluchng G6FO, were heard on the two,·al \'e receiver. The transmiller employed four vah-es with a Gl.6 as final P .A.

Although telephony from a police station in the north was strongly received, CSJU was unable lo hear other OX i.ignals. possibly because his QHA is surrounckcl with tall tree:.. al that time in full foliae;c. It is considered tha t these pre\'ent weak si!{Tlals reaching the aerial. GG\"C was \'cry acth ·e throu~houl the contest but only succeeded in working CGOT and G6PG.

In \'iew of the comparali\'cly large number of contacts rnaclc by G20A, it was unfortunate that his log was received after the closing date for the contest . Exactly what position he would have held it has nol been possible to determine as the mileages ha\'e not been inserted. He was heard, and heard others, at long distances.

The mystery sta tion was C61.l, :\lansfield, who \\'JS consistently putting a strong signal over long distances in all direct ions bul whom nobody could contact. It since turns onl th:\l G6LT was using a commercia l suporhet receiver which must have been badly out of alignment, as not one of the manv stations who called him was he.ird. '

The check log sub1nitted by 2CI L is a fine piece of work, all times being given to within 90 seconds. He received a remarkable nurnbcr of C.\\". signa ls on his two-valve receiver. which was operated on Ditchling Beacon. on the South Sussex Downs.

CSL\' found conditions poor on the whole, but reports hearing G5RD at much b'Teater stTength than usual . BHS2601 (Ewell, Surrey). heard, among many more, G6FO.

C6DH had a very unlucky week-end. Using a new superhet rccei\'er, quite a number of stations, including ON40J, were heard, whilst G6DH's own signals arc reported as being heard by several. Despite this, no contacts were cfTected.

2DL\\' , Bath, reports hearing G\V6AAP. G20A,

THE T. cS- R. BULLH1 /.\", :\o\'ember 1938.

C5:\J L, EIHJ. and E 12J , amolll-(St othc-rs, hut. unfortuna tely. gi\'es no time•, or corroborative details.

General N otu Jn add111on to the lari:c number of station~ act1,·c,

il is intcre,tml{ to note that mne entrant» wer.• at their home C?Hi\'s and ten portable. The proportion or u'en. of cont rolled transmitters to M:lf· excited is 1:1 to 6 much higher than in similar contests held in pre,·ious years. Not one of I he fixed stations u~d a self-exci ted transmitter.

:\!any entrant;; using ~tra1ght rccei\'ers remarked on the fact that numerous telephony carrier.; were heard and wlubt they were 100 weak to enable the speech to be rcsoh-cd. a fully re;1dable signal would ha,·e resulted if only the carrier had been keyed. i\Iany amateurs arc therefore pulling signals O\'er greater d istances t han lhey imagine but C.\\'. must be used, al least occasionally, to allow or identifica tion. :'llcntinn is made that the superiority o r c.c. transmission~ was most marked, it being possible to read ~Leady P.D.C. signab when only S2. The quality of llw note is the nnporlant point, the actual inpnl bcmg apparently a secondary consideration.

l\lost opt:rators found conditions part icularly good throughout the period of the contest , although rapid Carling was in evidence at times. One or two reported that ;,ignal strengths on the a\'erage were lower than durin~ last year'!> contest, but this mar be put do" n 10 the efTccl of the wet weather. experienced br many, on the apparatu~. The weather was d istinctly unfa\'Ourable, gales raginl{ on the lugh :.pots to the north. The moon was at its full on September 9, hut whether this had any effect on conditions on the U.11.F. is problematical.

A erial•

There i-. a certain amount of contro\'ersy al the pre:.ent tinw a-. to which is the most suitable type of aerial to u..c for all-round CO\'e rage. The contest has clone little to settle the point as many different types were used, all more or less successfully. The winner used a number or haH-wavc combinations, the runner-up :i. single haH-wa\'C dipole 35 ft. high. whilst those filling the third and fourth positions used long-wire acriab. The latter can Ix· \'Cry cffccti\'e but 1t ii. necessary to arrange part of the aerial in the \'Crlical plane, with the horizontal portion running in two or more different directions. Nadialion is then likely to be omni-directional. T he haH-wavc types give definite d irectional dTccts, which may he taken ath·anlagc of for world ng in a particu lar direction .

Windoms appear lo be out of favour on the U.H .F . as only one entrant used this t.-ype. Thert: is no don bl that it is difficult to get a \\"inclom to work properly when the foeder exceeds a fol\ Wa\'e in length . The aerial employed by G20A- a 1-1 i\lc. doublet 1s one seldom met with on 56 ~\le . but , judging by the results obtained with it, this type appears suitable for DX communication.

C2J I\ u:-.cd a single haH-wa\'e dipole, with a reflector placed 2 ft. or so behind it, " as per Kraus." ll is well to pomt out that such an aerial would act Ill a ,·cry d11Tcrcnt manner to a l< raus beam. a~ the reflector 1'- parasitically energised instead of l>eang energised directly out of pha.-;c.

The position regarding aerials can be summed up in the words of GW601<, who used several types: "There is apparently no uni\-ersal aerial for SG :\le.

,

TI/£ T. 6- R. BULLET/.\", ~on~mber 1938.

operalion. Signals a udible on one aerial arc entirely missinR on another type, e\'Cn though both were ' 'crt1cal or horizontal, as tlw ca-,c may be, wh1L,t marked chfferences in OH K \\ere nouccable when u ~ing two separate vertical or horizonta l aerials in double doublet fashion. To hear any particular "i!,'Tlal and to get the best out or it, it is necessary to rin~ the changes with e\·cry :ivailablc type at ha nd."

Concluslons

The re\·ise<I scoring system has fo und general {a,·our but se\·eral r:iisc the point that 1t was nor clear how many points should be taken for a contact O\"Cr, say. -10 mile;,. This will ht.• rectified next year. It is evident that the stations situated high above -,ca.Je\·el ha\·e an ad \-antagc O\·er those at low levels. Should a factor be mlroduced to correcl 1111~ or may it be considered that the M'COnd clas,, arc compensated by the fact that they work under t'a-;ier physical conditions ?

Tone-modulated self-excited transmitters arc t•apable or causing very severe interference, partly because of the broad nature of the signal and partly because the carrier is liable to spli t into several scl{ments. In ,·iew of the incrca•ing use of frequency

277

controlled tr.1nsnul lcrs. consc<Jnent upon the ca'c with which these may be built, either for fixccl or portable work. !>hould next year's conte,t lw limited to C.\\'. ) Or to frequency·controllcd lclt•phony ancl C.\\'. ? Should there be :i conle>t to c11courage listeners ?

The writer would be glad to receive a ny suggt•,. tion'i with regard to these points or to any othcrs which may occur lo the reader. in order that the 19'.i9 event 111ay be of even greater inten:st, bearinl{ in mind that it is desirable to incorporato a degrc·t• or progrc·s~ each year.

This " write-up" has already exceccled till' lcngth the writer intended it to be but, even !>O,

much informalion has had to be withheld. The log !>heets ancl reports arc therefore bcin~ made ava1lablc to anr member who may de~ire to study them, pro\·idcd postage is paid both ways. .\pplication,, which should be made direct to GSJ U, will be dealt with in strict rotation.

Fina lly. the trophy has been suitably engrawd and despatched to G \V6AA P. The writer thanl•s all lhoso who supported the contest and the many who have written him very interesting letters concerning it.

Contemporary Literature Bv L . FRYER (G:\!2FR).

A DIRECTION lNDtCA'roR Fo11 R OTARY A:-<TENNAS. L. C. Waller (\\12BRO). Radio, October, 1938.

A solution to the problem or a satisfactory direction indicator for rotatl\blc hcams. The nwthod described uses a home-made potentiometer with a high resistance D.C. voltmeter as the indicating meter.

The stable D .C. voltage ~upply of 250 \"Oils is oblained from the speech amplifier supply of the .1ulhor 's transmitter through one of tht: new coldcathode voltage regulator valves, the 0A4g. Full ,·onstructional details or a 32 point indicating system which has given trouble-free service for Sc\'eral months arc given.

• • • TllE R ELAXATION 0SCILLATOll ASI) STttEAMLINEO

Coo& PRACTICE SETS. A . \V. Fric11d (W8DSJ). Radio, October, 1938.

An article of interest to morse classes, or beginners requiring a cheap audio-frequency o~cillator for morsc practice. Two-watt neon or argon la mps arc used in relaxation type oscillator circuits, several ci rcuits with adjustment and operating data are given, the cost ranging from 92 cents upwa rds according to the refinements incorporated.

• • • I NOUCTl\'1' TliNlNG. Frank 5. )JcCullough

(WSllBU ex \\"GBE J ). Uadio, October, 1938. or interest to amateurs contempla ting the use

o f vacuum condensers for fin~tl tank tuning. The author draws attention to the points in which the v:iriable C. and variable L. methods or t.uning <Ii Iler. a nd illustrates the two met hods of tuning hy V<'Clor diagrams.

DIAL P110NE R t:: MOTE CONTROL. George M. Crcniug (W6HAU). Radio. October, 1938.

An in teresting article in which the 1111cstion of remote control is dealt with very comprehensively. J\ description is given of a system using the standard tcl<'phonc type dial and ten positio11 automatic t elephone selector unit by means of which two recciveri> arc switched on and off, switched from one to the other , frequencie; changed on a fhe channel C.W. transmitter, c\·erythmg at t he remote point (tbree miles distant) cut off and .1 local emergency transmitter and receiver cut in, and a direct talking ci rcuit between the control and remote points cut in or out. The system uses two pairs of line wires between the two points .

• * • A 100-WATT BANoswnc111NG Exc1nrn. Charles

\V. Hunter (\V6.8FC). Radio, October, 1938. A well-designed JOO-watt exciter giving full

output on any band from 10 to ·IGO metres by means of b:tndswilching and by means of crystal-switching and if necessary slight tuning of the final tank ci rcuit, any frequency in the above bands. Tlw unit. uses a 6A6 cryst:al-o>cillator-doubler, an 807 buffer or doubler and a 35T final amplifier.

• • • REMOTE FRhQUENCY CONTROL. Frank C Jom·,

(\\"6AJ F). Radio, October. 1938. The author who is well known in the amateur,

world, describes a unit designed to allow quick frequency change over a good portion of tlw 20 metre band. The unit uses three 80 metre crystals in a Pierce crystal oscillator using a 6C5 or 6C5g rollowed by a GJ5g acting as doubler or unneutralised buffer. The oulput circuit is link

278

coupled to a ..,pcc1al 40 metre tauk coil which is plugged into the c rystal '>()Cket of the main tram;mitl<'r unit. The unit a~ dc,cribcd measures 7 h,· 7 bv 11 inches and can be placed along~ide thl· rccei~·er enabling ;t range of frequency 'hift without touch111g the mam transmitter.

• • • T11 1; X Ewco,11ms SPHCI \I.. Jack Rothman

(\\'GKFO). Radro. October. 1938. An excelle"Ot beginnl•r 's t ransmrt lt'r is described

in this article : using a 42 as cr::stal oscillato r and a fiA6 as final a mplifier tlw set will put about 15 to IR watts into the ae rial when ' upplicd with 350 \'Ol t s I £.T .. whrle with 300 \'Olts on both anodes about 12 to 15 watt." output may be expected. Full com,tnac tional a nti operating data, a nd a list o f a lternative valves arc included . .. • • A UROADCAS1 TYPI! ;\! ODl: l.ATION INDICATOR.

Henn· G. Jone:> {WGGCT). Radio, October , 1938.'

The author tlcscribcs a mod11 l;ition indicato r ha,·ing the lo llowing foat11res: cas<' of ad justment, a pcrcen lage-calibraled ins trument with a rapid up-l>wing which docs not go too far on the peaks and at the same time has a slow return to avoid bouncing, a nd ;t mean~ for i ns tantancous indication of peaks over a ny tlcsirod modulation percentage.

Jn addition to general monitoring the a mplitude and frequcncv cllaractt-nstic..; of the transmitte r ran be taken 1f a sui table audio source is a\'ailablc. F111l cons tructional a nd calibrat10n data is g i\'cn.

• • • J :-;vERSE F1rn1>nACK FOR \ \1., n:t:R PHo :-oEs. \\°ill

A. Bell (\\'liJXS) Radio, c>rtobcr, 1938. An interestmg description of an inexpcnsi,·e

~,·stem for n•ducing d1:.tortion in the a udio frc11uency :.\·stem and Jl(•aks t.hroughout the audio range to a ,:err small J><'rc<'ntagc a -.imple in\'ersc fc~'dback regenerator co,ting S l.50 to S2 00 is applil·d to thc audio system. The th~'<lry, 111Mallation and operation of this method b di;.cu;,sed, a nd the circuit diagram is incl11d1·<1 in tlw article.

• Tt1E 15·WATT C. \\°. TttA:-os\llTTER (G2HJ.; ) Tele-

visio11 a11d Sltort- ll'a1•1· ll'nrld, Sept ember. 1938. This short a rticle giv<•, additional information

on the s11h-clt as~is layout and a power s11pply suitable for the 15-wall C.\\°. tran~mitter dc~ribed 111 thC' July issue of th~· magazine

• Tu& BEGINNlm's 2-VAl.VIC .Rucmvrm. G5ZJ . Tele

visio11 and Shorl- Wauc W01•/d, Scptemb<'r, 1938· A description of a two valve vers ion of the s ingle

\'ah 'e receiver described in the August issue of the magazine. Built to provide loudspeaker reception on the short waves it uses an SJJ2D as detector followed by a P en 220 output valve.

• • .\ Su1PLR REci;1v1m FOR TPLi:;,·1s10:-: 501::-:0.

T elevisio11 a11d Sl1orl- ll'acc: W orld, September , 1938.

Designed fo r reception of the Alexandra Palace -ound tram.mission only. the receiver u!'Cs an SP4B as detector with capaci ty controlled reaction, r~-i.1stancc coupled to ;i Pen 4VB The tuning is performed by pre·scl trimmer type condensers which should require no attent ion after the initial ,,etling. A power supply using a metal rcctifieris included in the ci rcui t

THE T . c;. R. JJL'l.!. I:.Tl.\', :\ovemhcr l ~):!S

P11As~:o .\:-:TE:" :O:A S\'sTEms. Bryan Groom (G:\IGRG). Tdevisio11 turd .Slrort- ll'ar•r W orld, Scptemlwr, 1938.

The author dc,crih1.•s an :icrial system winch he ha~ c\·oh·1.·cl a~ a r6uil of con,,1dcrablc cxp..•rtmental work. dt!ta1ls of which arc giwn

The aerial tlcscrih1.•d 1s most suitable for amateurs ha,·ing a high mast.

• • • X oRFOLK .\ \IATEt:Rs PRt::P.\R~ FOR ElrnRGE:o:c1Es.

Fenton Priei.t (\\'3E:\Dl) a nd Lauri1.• Turn\.'r (\V:mc;K). Q.S.T .. Septeml><:r, 1938.

An inlcr<·sting dcsrription of s tandardised trans· mitt.ers with inkn:hangeabl<' power >upplic" for tlexibility 111 cmcri:cncy work.

The transmitter uses a 6Fti as cry,, ta! o-,cilla tor and an 807 as final amplifier in the R .F. ~ecti()n . with 6J7, HC'5 a ncl Gl .Ci valves in the audio srction .

Two power supplies arc available, one A.C'. deli"erit11{ :1so \'Oils. one D .C. with Ci vult input <lt•livering :JOO volb. On A C. the puwer input lo the lina I is 25 tn :rn watts on phone a ncl :HI w 40 watts on C.\V.

Two crystab and two coils 1.·ovcr tlw fo ur band• from 1-1 to 1.75 ;\k

• • • PRESKl.ECTI0:-1 S1Ml'C.t1'11rn. T . )f. Ferri ll, Jnr.

(Wll .J I ). (}.S .'J' . , Septc111h1.•r, 1938 The author de•crthl'" a n efl'cdh·e onc-vah·t· R.F

amplilier with switching for hvc band,, Full building m~tructions mcluding details of p.rncl anrl chassis. a nd coil wmdinss a rc• inchukcl Thl' amplifie r will work ahead of a ny rl'rc- iwr and should make a very usdul u111l

• • ixTERPRl>Tl:"G 1938 '.., 56 ;\f1'(; \("\'CI.£ T>X j .. \

Pierce (\\°IJFO). Q.S.T .. S<'ptembcr. 1938. This article dea ls with the ch·cluction of Iono

"Jlhere conditions from long-d1sl<111cc amateur work on fin• ml'lrc>s. and while deahng more particularh· with :\nwrican con1htiom. j,. of intl•n·st to all a ma teurs

• • • .\ F1\'E-llA:O.:D SwtTCtll:O:G EXCITER WITH 807

OcTrn. T I' Kinn (\\' ICC) <! S 7 . Sl'ptcmbcr, 1938.

T he a rticle dcscrihes a neat l'XCiter umt designed to euahlt- a I kW. transmitter to he controlled from the operating tablt.>.

The 11111t incl11d1.·s two ,cparall' o;,c11lator,,, one cn·s tal controlled a nd the ollwr self-controlled. b,:o frequc 11ey multiplving s (fl f\cs and an 807 output stage.

Two power supplk~ an· provided, ont• for thl' two oscrllators, and lhl' othl·r for tht: multipli<'rs and output stage.

The crystal osci llator u8es a t ype 71l vak c in a s traightforward c ircuit in which thl' t uning is done h,· means o( the , .,tl,•e and miscella ncou-; ci rcuil capacities, the alli:rnati \·c EC O'iCillator using a t~·pc 89, the plate l 1rcuit of which b agarn of the semi-tuned type.

Type 6F6 val\•es arc used in the two multipli<'r stages followed by lhc 807 output, and to enable the operator to monitor C. \\° tr.lnsmis..ions the unic is equipped with a type 61\S , •alw which w?rk-. similarly to <L miXl'r val\'e 111 .l supcrhct receiver

A type HX5g :.cr\'l'S ao; rectifier for tlw oscillator power supply with .1 type S:! in thC' ,,t•Cond power ~upply circuit.

·111£ T. c!-- N lll 'Ll.£Tl.V, :\ovcmbe1 19:18. '.!79

A ny 10 Stations can be pre-set on this de luxe

'' HlS MASTER'S VOICE~' ,-/

lt' V AL VE -~ 4 WAVEBAND I

CON5!.LE RECEIVER ·wITH PU/ sH-BUTTON TUNING

,/

Autor natlc tuning by "push button " which makes it Pd ssible by simple adjustment co pre-sec any cen mec' !um-wave or long-wave stations ... aucomacic fr<' .quency control .. . variable selectivity ... a con-t! nuous tone control ... automatic volume control ...

separate bass and treble controls ... true-to-life tone ... and a walnut cabinet of modern design that is a triumph of furniture craftsmanship, combine to make "His Master's Voice" Model 659 the radio achievement of the 1939 season, capable of a " really hoe " performance. Model 659

Cu~ Price JI Gnt

TUNING BY AUTOMATIC HAIRSBREADTH FREQUENCY

'Specification in brief: 10-v3lve -superhet with AVC ... 3-valve . automatic frequency control circuit ... 10 station push buttons with change-over manual luto button . . . Quiet tuning ensured by muting L.F. circuits between

·stations ... Direct station to station movement . . . Large tuning scale illuminated according to waveband In use . . Four

CONTROL wave ranges. 13.5-34, 34-100. 200-550 and 750-2,000 metres . The tuning circuits are particularly sui tab le for the reception of all the S.W. broadcast bands. 13.5. 17, 19, 25, 31 and 49 metres .. . Mains aerial contact ... Fluid-light tuning indicator ... Vernier scale ... Combined volume onfolf switch . . . Variable selectivity switch .. . Manual tuning simpli-

fled by Incorporation of special 1.F. circuits . . . Sockets for connection of gramophone pick-up .. . Separate bass and treble tone controls . . . Elliptical mains energised loudspeaker ... Sockets for connection of external loudspeaker ... Switch for silencing either external or in ternal speaker ... Output 8 watts . . Consumption 100 watts.

40 · Yt~·RS'· 'SOl.!ND' E'·XPERIENCE

280 THE T. 6- R. BULLETIN, ?\ovcmbcr 1938.

ecun· \ mg ORDER EARLY BEFORE T~E RUSH

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THE T. cS- R. BULLETIN, ~ovember 1938. 281

Ry J. K. WALKJ::R {GSJU) .

Part XV. - EXCITAT ION AND B IA S

BEFORE a valve ca11 perform a ny useful functiou it is necessary first of all to supply its electrodes with proper fixed \'Oltages.

a nd second, to apply an alternating voltagc to the contTol grid. When this latter voltage is at radio frequency, it is termed "drive" or "excitation," and upon its strength depends the conditions under which the valve operates. Also, for R.F. applications. the 11egative grid bi;Ls voltage which must be applied is dependent on it. so that bias and excitation can well be con~idered together.

Tt is desirable to commence with an explanation of (I) various operating rontl1tions it is possible to obtain, and (2) the basic n1les governing the mode of operation which should be used in different ci rcumstances.

Cius A Operation In audio frequency work. it is necessary to obtain

an output which follow-; the original signal as closely as possible, i.t., oue which is undistorted. It is. therefore, usual to adjust the operating voltages of the valve to give what is known as Class A conditions. That is lO s:\y, the grid bias is set at a value which. at the particular anode voltage applied, results in the working poin t falling midway on the straight part of the ch<1racteristic curve of the valve. The grid potential must not be ::illowed to become positive :it any instant, otherwise grid current will flow. This would result in a fl attening of the peaks of t he applied voltage, with consequent disto rt ion . T he applied voltage, measured from the positive to negative peaks of a cycle, must not exceed twice the ncg::itivc grid ~·oltage. In practice it will be somewhat less, due to the necessity of avoiding opcrnting over the curved portions of the characteristic curve.

The Cl::iss A type of amplifier may also be employed in radio frequency service, but, because of its relatively low efficieucy, it is seldom used. The a node dissipates considerable energy continuously, and only a small useful portion appears in the output circuit.

Cius B Operation For any given anode voltage, there is a value of

negative grid voltage which will exert :in influence on the electrons emitted from the cathode sufficiently st rong to prevent ::inr of them reaching the anode : in other words. no current flows. This is termed the " cut-off voltage," ::ind may be found

by (a) studyiug lhc anode current/ grid voltage curve, (b) by dividing the a node voltage by the amplification factor of the valve, or (c} by practical test. The latter may be carried out "·ith simple apparatus, ::ind :is the vah·e may vcrhaps be used under conditions somewhat different to those specified by the manufacturer (let us hope the ::inode voltage wi ll be less, and noi greater I) it is the most reliable. Fig. l indicates the circuit to set up for carrying out such tests, the variation of grid potential obt::iined by means of dry batteries being com·enient ::ind sufficient!)' ::iccurate for our purpose. The b.uteries should be in good condition so t hat the marked \'Oltages can be relied on. It will usually be known roughly at what value of grid bias the valve operates normally, ::ind the procedure will be to st::irt with a value considerably higher. and gradually reduce it until anode current just commences to flow, switchmg off the anode '·oltage each time an ::ilteration is made to the grid tap.

Working the valve at the point so found is known as Class H operation. During the negative half cycle of ::ipplicd volt::igc uothing happens, as the grid is simply being made more negative : during the positive half cycle more or less ::inodc current flows, according to the value of the applied voltage. As this may ::igain l>c uearly twice the value of the standing grid voltage. without running into grid current, tho output will be considerably great er . F urther, as the valve only passes current during alternate half cycles a nd during the lime that useful energy is produced in the output circuit, the efficiency will be higher.

Clau C Operation

Under the conditions so far discus~ed. no grid current has been a llowed to llow, and no power has been absorbed by the grid of tho valve. It is permissible to incrc::ise the excitiug voltage to a value greater th::in lwicc " cut-off," but if it is carried lO excess. sc\·eral things will occur. Current will flow between the grid ::ind cathode of the valve and, as this path possessc:. considerable impedance. the d riving power requirements will increase to make up for tbe loss. The anode current will rise very rapidly, and may reach values which, being maintained over the m::ijor portion of each positive half cycle, will d::im::igo the valve.

To mitigate these effects, it is necessary to still

282

fu rther in..:rcase the s tanding bias, wlwn the conrlition known as Class C operation is obtained. The posi tive half cycl<' has now to cancl'I out the amount of negative voltage beyond the cut-off value before anode current flows, so that the latter actually only flows during a portion of the half cycle. Ouring that portion, however, the rise and fall is extremely rapid, n high peak curn·nt flowing moment<irily and hig h p<':lk ,·oltagcs being generated in the a node ci rcuit. The etficicnc\· is a~ain increased but it is necessary to e nsure that tlw valve employed has been desii;ncd with ampk cmis~1on and well-spaced electrodes to make it suitahll' for such operation.

Fig. 2 illustrates tht· types of a nodl' current rlow met with under the three condi tion~. Class A results in the output ci rcui t being supplit•d smoothly a nd practica1h · continuou~ly "ith oscillallng e nergy o n the fundamental frequency. the amount of harmonic e ne rgy being very small. C/a(.\ II may be considerC'tl to gently kic k the output \' ircuit into oscillation, with a rathe r greater amount of ha rmonic ou t put. Clas.( C kicks the output c ircuit ~harply for brit'f and comparati,·cly w<•ll-st·paratecl periods. which action gives rise to tlw gl•neration o f s t rong harmonics. Two points emerg<.• from the use of ~he Class C method of operation one is that the output ci rcuit must he capable of "wnng e nergy to carry it over lhc periods during which it receives none from the valve; the other, the dt•sirability of making the output circuit sharply rc'°nant to the fundamcntal frequency M> that th1• harmo nics arc not given a chance to build up any appreciabl.: energy. The firs t point is taken cart• o l hy us ing a certain minimum of capacity in lit<.' tank c1rc11it, to en:\ble what is known as the " flv" lwl'l elTcct " to occur, a nd the second by keepi;1g llhscs very low.

A mount or Exdtat.ion Required

It is no w usual for the manufac turt•r o f transmitting ,·ah-cs to !>pecifv the d ri,·ing rt•quircments of each partic ular type.' Although th t• me thod of doing so i!i not Btandardiscd, it is becoming common p ractice to q uote a figu re of so many grid mi ll iamperes; where this is g iven , no diffic ulty wi ll be experienced. The figure is usually th l· maximum \-alue recommended. and should not under an\· ci rcumstance!> be cxcrcdcd : in fact. tt 'hould ~ possible to obtain perfectly satisfactory results with a g rid current considerably lcs~ than the maximum. Again, tht: actua l value o f grid current. as read on ;1 met er ins1,rted in thc 1·arthy side of the grid chok<' o r resistance, is dependent · on q uite a numbt•r o f fac tors. such as the anoclc circuit

l.JOt; >t.T B_.rr

;Ji+-I I

:~';v I

' H.T.-

Fiw. I . A simple m#t hod of determinin, the oalu«! of c ut . off bio• . In t he •ca•e of a pentodc. the screen will be set at normal opcrati n, uoltowc. The oohmeter V is a refinement which may be added if de•ir cd.

THE T. G R. BULLETJX, ~ovember 193$.

loading, anode voltage, and grid bias voltagt·. The figure specified by the mak<'rs is that which >hould he obtained unde r working conditions, i.t'., with 11.T. ,·o! tage applied to the a node, with the a11ode circuit tuned to resonance and loaded, a nd with 110 fixed bias applied, the bia~ for the grid bt:ing obtained from the ' ·oltagc drop across the grid res is tance, the \ 'a luc of which shoukl be sulticic11tly high to enable the valve to run under either \lass B o r C conditions. 1t is, howe''t• r, <il'sirable to 111clude at least a certain a mount of foxed bias in order to prevent high anode curn•nh flowing when no excitat ion is applied . The addition of such tixcd bias will recl11 cc lhe grid currcnl .

ll is well to mention he rl' that it is p1·rfcc lly no rmal for a g rid milliamml"lt·r to show a much higher reading when no nnode voltage b lX'ing applied. T!w reduction. on applying tht· latter. will be 50 pt:r cent., or ewn more. due to th1· fac t that the anode att racts tho'c e lectron' which previous ly hit the g rid .

)fatters arP some whal rlitticult when till' driving require me nt s are specified in wa t ts or in tilt: peak RF. voltage. The only rcli :tble way to arrive :iccurately at the R . F. \'Olt;1g<' which is being applied to a \'ah•e i~ to measure it with a ~·aJve \'Oltmetcr. a lthough a very rough ei.timation may be obtained hy using the pnnciple tha t a rectifier of the type formed by tlw gnd cathode pa th of the valvt• g i\'('S

-a D.C. voltage equal to the p<'ak of the alt..rnating voltage applied. Jn the prcst·nt case, this is no t s trictly tru<', because o f tlw effect of rlu.· lo:td represented by the , ·ah·e and hy the grid n·-;1'ita11C<.'. hut the voltag\• dc,·eloped aero'' the grid rcsi, ta n tl',

·as measured hy Ohm's I .aw (the actual rcsi-tancl' and the current flo"ing throug h it being known). will ~en•e as an indication .

The driving power requ1n•d by any particular vah·e is the amount lo~t 111 the g rid cathode palh, and may \'ary cnomiously, 1htl' to the fac t that the 1mpC'clancc of this path is not a fixed \'aluc, but varies with the conditions und l•r which the \•alve operates, and with the applied vo ltages. Jt will be grtatest with a low capacal~', low magnification type o f v<dve, in which the grid consis ts of an ope11 nl t•sh well spaced fro m the other «kctrodes. The 1mpcclancc will be low in the ta~c of pentodcs and Class B \'alves, which haw :l dosclr wound 11rid mounted near tbe cathodt·. Ef!ects tend to lt·,·cl o ut, however, owing to th l' fact that the lo" µ. valves require a high driv ing voltage, whils t the Sl'COnd class do not. The actua l choice will often depend on the frequency at which the va lw will work, for reasons outlined lah-r.

The osci llator s tage mus t be capable o f supply111g . 1 good deal more power than thal specified a' being necessary for the val\·e, if a :.:His factory pt•rformance is to be achieved. A certain a mount ·~ db:.ipatcd in t he grid circuit it>elf, and this i-hopld, there fore, be designed with carc in o rder to 111111imi~e lo~cs. If tlw grid ci rcuit consii.t s o nly of a coupling condenser and choke, the fact that these a rt· :\I a high R.F. potential will introduce !Osse;., whil;;t in an ordinary lUncd ci rcuit the ohmic resis ta nce of the g rid coil , eddy currents , e tc .. will do likewise. T hen t he grid res istance will auwrb a C(• rtain amount of power. especially in the case where i~ is callcd upon to pro,·ide a ll the negath·e bia~ the ,·a lve requirt·s. To minima~<' tlus Joss, it is a1h ·1!--

. • 1blc to provide a large percentage o f the bia-. from

·1 HE T. 6- U. 8L"LLETI .\", :\m·cmbcr 19:18.

.rn external ~ource, whibt s till retaining a certain amount of resistance. The benefit of the l:1llt'r is that. ru; the drive increa~cs, the voltage acro~s the rt•sistancc will also incrca~c so th:1t the bia~ is, to >ome extent, self-adjusting. Jn practice, it 1s well to allow for an output from the previous stage of t" ice the power specified as being necessary to drive the valve.

The rca!-On why it is not desirable lo exct·cd the maker's figures in the way o( grid current or power 1" because the grid, which is situated betwet•n two hot electrodes (the anode a nd cathode), cannot casilv radiate awav heat and its dissip<111011 is therefore very limited. Should the valve be seriuusly overdrfren. the grid may become w hot that -ccondarv emission will commence. and tht' ,·:11'·e will be damaged. It is probable that the life of many a valve has hcen cnt short throu!(h t his l'(llJSC.

One other point may have puukd the rt•:\der \\l\<'n studying a valve data sheet. Thi" is the figure , tating the maximum R.F. current which may be a llowed to now. The reason for thii; heing sp<•ri licd 1s that, under certain comlit ions. a high value of lurrent mav circulate a round a tunrd circuit. of which the , ;alve clectrodes form a part. The "ires lt•ading into the v;1lvc throush the pinch arc m;1de usually or line platinum. and if they gel vrry hot, there is a possibility of the seal being da magl•cl a nd the \"acuum or the vah·e destroyed.

T elearaphy and T elephony The excitation required by a valve dept•1uls on

the amount of radio frequency power it is dl'sircd to produce in the anode circuit, ~nd this again :~lso 1icpends on the anode voltage. \\hen t~e latter 1s a fixed quantity, as pertains whe1~ .conbnuou" wave tt•legraphy is cmploye~. th_e .cxc1t111g ''<?ltagc n~nst ht• sufficient to result 111 ethc1ent Class C op1•ra11on. :11111 all is wt•ll .

\\'hen anode modulation is used, the anode voltage is not con~tant, hut is ,·a rying each side 11( the -1anding ,·alue by an amo~mt depending on fhe 1kgree or modulation. 1.f this 1s 100 per cent .. th.e anode voltage doubk·s 111 value on peaks, and if modulation is to he linear, the anode current must • 11'0 double On peaks of modulation. therefort'. the mput is four times the normal. power, and ~he l'Xci tation applied must be sufficient .t? fully drive the valve (still under Class C co11<11t1ons) at t·he increased input. Should the excitation he iusulliucnt, it '"II not be possible to obtam full modula-11on, irrc>.p1>etive of the power delivered by the modulator, whilst ,.hould the latter be allowl'cl to ,.wing th1· anode voltage to a greater dcg:ce tl!an the excitation can take care o(, severe d1stort1on will result .

For correct t elephony opcrnt ion it is nec1·ssarr 10 either increase the exci tation (and the bia;.) , or to reduce the· working anode ,·oltagl·. The latte r is more usual in order to ensure that th <• valve is not bdng overrun. . .

\Vhen the stag<' preceding the power amphher 1' modulated the excitation to the latter varies at audio frcquc;\cy. For linear modulation in this p;lrticular case. the bias and anode voltage mus\ be .1djusted ~o that the valve operates under Cla,s B tonditions.

The remarks so far made apply to what b known .ls a single-ended ~1:1gc. 1.e .. one using a single \'alve. When t'wo valves arc conncctecl with h<;o\I} thr grid~ and anodes in parallel, the dicct i~ the

283

~ame as if a largt' r \'al\'c of lowt·r impedance had been "ubstitutcd. anti the btage is still actualJy single·e11ded. l ' n(kr t'l:t"" A condition,,, thl' same amount o f dri\'e would suffice (lea,·ing out the frequency effect). but under Class B and C conditions twice the grid current will be necessary. and also twice the excitation power, if the R.F. voltage applied 10 the grids is 10 remain the same'.

\ \ 'hen two valves arc employed with the· grids connected one to each side or a tuned ci rcuit, i.e .• in push-pull , only half tlw R. F. \'Ol tage available across thr whole ci rcuit will be applied lO each grid. 111 t his case again, the excitation pow(•r must he increa~cd to bring the applied voltage up to its proper value.

Oe:si1n of the Grid Circuit :\ ci rcuit which consists of a largt• value or induc

tance and a low value or capaci ty (i.e., has a high L C r<1tio) has tlw property of developing \'t1ltages which may be much higher than tho::.e which occur tn the ci rcuit from which it derive~ its energy. Thi· peak voltages, al t hough tlwy only last for a minut e fract ion of a second. may be suflicicntly s trong to cause <1 high peak current lo flow between the grid a nd cathode of the \ <lh "<'. which current will not be 111dicate<l on th<' grid meter, as the latter only reads the average value. To :LVoid thii. effect, which wi ll do the valve no good. it is wise lo .1rrange the constants or the grid ci rcuit "° that a mock·rate 1. C ratio obtains. bearing in mind the frrquency 111 use. The only dcparlurt· from this is when the tlri\'in~ po wer avai lable is on the low side l1nder this condition a certain amount of bt·nclit will result from aUow111g the \'Oltage to build up in a circuit of high L1C ratio. The moderate I, (' ratio will re~ult in an additinna l benefit in the ca'e of a driven a mplifier through the ,·ollage being of a more ~11111soidal nature (that b to ~a)". of a smoother waveform), consequently less harmonic output will he produced .

Effect of Frequency :)o far liule h<L'l been ,,aal about the elfect of

frequency on the· 11 mount of excitation n·qui red. Actually. the amount required by t he grid of the ,·alve, under any gh·en se t of conditions, is constant . 1rrespt.~t i\'e of the freqm·nc\·, which is t he reason why manufacturer, do not -;t atc the frt•quency

IZO

~90 ' .. ! " 60

I ~ A ~ A " I I ' I

30 \

I I ' I \ IC • c " <·- .. --·-------- .. ~ .... ---··--------- 'r

r.....,c " .,,,, ~,,,,.,,.. o~r~ "'MT1'•c c~~,.

Fi#. 2. lllustrat inw the Row of anode current under differ~nt c/osse• of operation. A : .teody moderate c urrent, B: curre nt pas•e• only clurine- positive holf cycles, C : peaky c urrenr durin g portion of po1itioe half

cycle.

284

when >pecifying the driving requirements of valves. \Vhat docs affect il is the input capacity of the vah'e, upon which also depends the input impedance. The grid and cathode (in filamentary vah'es the filament is also the cathode) form a condenser and. as the reactance of a condenser decreases with incrcai.ing frequency, the by-pass effect it t:xcrts bccomei. greater. On the lowt•r amateur frequencies, the power applied to the grid is almost wholly dis~ipated as heat on the grid , bul, on the high frcqucncics, considerable dielectric losses aho occur. The re,.,ull i::. tbat additional power must be provided to make up for the loss so that the grid proper is still being supplied with the correct amount.

The above explains the apparent falling off in cftic1cnc\· of pentode \'aJ\·es at tlw \'cry high frcqucncic~ : the high input capacity rewlling in poor pt•rformam:c. Low capacity triode va lves, opcr.ited under wrrect conditions, will almo>t invariably pro,·e mo~t suitable.

The low input impedance or high capacity vah·es m;i kcs it d inicult for R.F. voltage to d t! velop in the input c ircuit, unless excessive power is availuble, a nd untll·r such d rcumstanccs it is of little use making the input circuit of high L , C ratio in order to trv and correct this effect. Tht! only solution is lo tap the grid some distance down 0 11 the grid coil - the damping effect of the \'alve will lhen be less, H. F. \'Ollage across the circuit will be higher, and, due to the better matching. the grid will aclllally have impressed upon it a higher voltage than if it "ere connected across the" hole circuit. This should hc borne 111 mind when <lb.appointing results ha~·e Jx:cn obtained from a oentode or, for that matter. (mm any valve of low ·input impedance.

Blas

1\ s the cut -off point of a va)\'C depends on the <i nodc vollage applied, so also will the amount of workini.: negative bias voltage. This is usually s tated br the manufacturer , and should not be departed from to any grea t extent

The greatest power amplification occurs when the valve is biased to cut-off, but the efficiency is unlikely to be greater than 50 per cent. lncrcasiog the bia~. which a lso necessitates increasing the drive. re~ults in an incrl!ase of efficiency. but a point is soon reached at which the process becomes uncoonomical, and beyond this point the drive has to be increased out of a ll proportion to the extra l·fficienc\' obtained. Jt is usual to bias a valve employed as a power amplificr to twice the cut-off voltage. If plenty of drive is avai lable, the bias may be increased to three times cul-off and the t•xdtation increased accordingly, hut as this proccss will result in the grid being required to dissipate three o r four times more energy, it is well to make sure that its dissipation is 11ot being exceeded. In this connection. a transmitter used for CW (with a i.tage prc\'ious to lhe P.A. being keyed) may be a llowed lo run at higher power than a telephony transmitter because of t he intermittent nature of the currcnl flow.

A \'ah·e employed as a frc11ucncy doubler operat es al a lo" er efficiency than as a power amplifier, and to keep the efficiency as high as poss ible, it is desirable to apply a high excitation voltage and bias back in proportion, prcfcrablr as much as four limes the cut-off value bei ng applied . As previously pointed out, this entails tht! danger of over-running the grid a nd, to avoid this, a va lve capable of

THE T. 6- ll. 13ULL£TJN, Xovember 1938.

d1ss1pattng both the gnd mput power and that lost at till' anode ~hould be chosen. In other words. the excitation applied to a gi,·en val\'C used as a doubler mu~t nol exceed that for which it 1s rated, whibt the anode , ·oltage and current must be reducl'd lo ligurcs below t he maximum specified for power .11nplifier operation in order to a llow for increa>ccl internal dissipation.

The \'ah·e cho~cn for this position should h;tvc a high magnificat ion factor, as the cut-off volt.age will be quite low ; otherwise it will be uneconomical to pro,·1de the high negati,·e \'Oltage necessary. ~pecial types arc now a'-ailable with which \'err little anode current flows at zero grid bias, and t hese are \'Cry ~uitable for operation as frequency doublers.

Effect of Anode lmped;ance :and l o;ad

Bound up with excitation and bias arc t he constants of the a node ci rcuit, including the impedance of the anode/cathode path of the valve, the a node ,·oltagc, and till' optimum load into which the \'alve should work. These factors will be discussed in a future art icle.

TRADE NOTICES

Sho1·t IJ'ave Rudio, Ltd., 97, Park Lane, l.ccds I, although a comparatively new company, ha"c already estabhShl'<i themselves in the amateur radio market A. ''e recently had an opportunity of examm111g some of the wide range of component» they ofTer, the following comments may prove helpful to members.

Their transformers and chokes (including a swinging choke 5; 20 l-l 200 mA.) are of robust construction, of good appearance ;\nd moderately priced. \\'indings are. in most C.'lses, brought oul to loosc leads. \\'e should ha,·e preferred the u~c of tt-rmina l s trips. All transformers have been test<:cl to 3,000 volts.

Variable condensers range from 160 to ISµµF. In addition the lower values (from 15 t-O 45 µµF) a rc offered with .094 spacing. Although modestly priced these ccmdenscrs should s tand up to good sen·1ct· i11 receivers and low power stages of transmitter. Bras~ 1s used for \'anes and supports and a ceramic matt•rial as insulation.

Power resistor:. range from 10 lo 100,000 ohm:, in 10. 20, and 40 watt ratings. These arc Austrian made and \'Cry cheaply priced.

lmpex valve» (including 6L6G's at Gs. 6d.) arc guaranteed for 12 months against normal failure .

Short WC1ve Radio Co. are equipped to g rind-in l wall carbon rcsistors to 2 per cent. limits or better.

F urther dcltli l~ concerning the products handled by this company can be obtained fro m the addrc:;,, quol\!d

* * * The A 11/0111atic Coil 1Vi11der Co. , Winder House.

Douglas Stree t, London, S. W . l, will be plea sed to send to interested members a copy of thei r new folder, gi\'ing comprehensive particulars of thei r pr~ucts.

For 28 Mc Listeners \\'Gl:\'LS will be pleased to QSL JOO per cent. on

a ll reports , prnvided these are accompanied by a n International Coupon.

NIE T. b R. BULLE'f!N, ~O\'ember 1938. 285

Experimental Section )IA:-:AGER, ,\, )[. ll. FERCt;S (G2Z\)

D URIXG the recent cri~is acuv1tr in most

Groups was at a low ebb, but the Group )fanagt•rs report that an improvement is now

taking place throughout the Section. The Aerial Group under G2Dl is still undergoing its process or re-organisation, but it b hoped to publish details of their arrangements in rhc next issue. The Aurora sub-group have produced a much enlarged monlltly magazine which now incorporates a section dealing with thc )loon. l'rofeo;wr Carl Stormer is supplying this group with aurora observations made at Oslo and other stations in Southern Xorway. a nd his notes cover thrcu pages of the October issue.

DX Forocas t Following on the successfu l forecast made in the

September issue of A111·orn. the group now fo recast that conditions arountl the period December 2-3 will be simila r to those which prevailed during midS1•ptember.

Cosmic Dau \\'c feel it desirable to record that only nine

members replied to the question asked in the last issut· of the llUt.t.ETIN regnrding t he Cosmic data which has been prepared in recent months by .M:r. j. C. Elmer . The suggestion has been made by one member that as t he B.B.C. obtain information from Greenwich (reference Page ? 10. October Bt1LI.ETL:-:) il would perhaps be better to publish this, which is up to date, rather than details which arc a month or two old. Experimental Section members are requested to advi~e their G.)f.'s on this point, whilst non-members of R.E.S. would oblige by addrc-;sing their views to the Experimental Section :Manager.

Eclipse of t he Moon Srction members who have completed logs

covering the period from 1939 G.:\I.T., Kovember 7. to 0 114 G.?II.T .. :-:ovember S. and who noticed any effects lhal might be attributed to the Eclipse are requested to scud detail!. to :'llr. S. W. Allcorn. 2 F ll l , Leighton l-fouse. Holland Park Road. London. W. 14. Group Ct·ntre of the Aurora subgroup. Mr. i\lkorn report!. that the total eclipse started at 2 145 and ended al 2308 on 'November 7.

Me mbership The rules of the Scclion arc being reviewed

followi ng discussions during Convention, a nd although nothing has yet been settled it is generally felt that U1e hlllOOth running or the section. can be improved by restricting entry to Group members only. lt has hecn freque11 tly pointed out in these columns that lnclividual membership is or little or no value. Such members arc again urged to consider applying for transfer to Group membership.

There are a few members who have failed to send in any report of their activity although they have received individual notices from tht:ir Group manac:er. To them we would point out that the rule~ dealing with activity and "ith the renewal of membership (which takes place at the end of nex-t month) arc to be strictly enforced. It is t he opiruon of tht· Group i\ lanagcrs that failure to report indicates lack 0£ inl!'rc<it: it has therefore been decided to enforce this rule by cancelling the membership

of tho;,e who fail to report. It should be mentioned that although tht• rule specifics a thr('e months limit. we have 111 point of fact allowed more than si." months, so that with thi~ reminder those who find their membership cancelled can hardh· claim that they have not been ach·i~cd. ·

Before passing on to the Croup :Manager's reporti., the writer would like to t•xpress his gmtitude to those who ha,·c hacked the Section ;,o well.

G2ZC Prop31·~tion G roup

T he dist urbed I ntemalional situatio11 nt the end of September has had its cficct on the October Letter Budget~ of the variou~ groups a nd nearly a ll arc smaller than usual.

A system of 28 :\le. Character Figures has been suggested by G2XC to show a t a gla nce the variat ions of conditions from cl :ty lo <lay. T he met hod

Cosmic Data WIT H REFERENCE TO T HE APPEAL

MA DE BY T ll £ EXP E RIMENTAL SECT IOK :\lANJ\GER IN OUR LAST ISSUE, IT JS \\'ITll RECH.ET WE RECORD T HAT O~"LY );!);£ )IDIBERS H A\'E WRITTEN TO ASK FOR THE COS:\UC DATA TO 13E CONTINUED.

IN VIE\\' OF Tll E LACK OI~ IKTER EST A);D !); FAIH:-."ESS TO T HE CO);TR TBliTOR- :\IR. J. C. EUlER, G2GD-WE ll A VE DECIDED TO DISCONTIKUE PUBLICJ\TIO~.-ED.

which is being tned out by all t he 28 :\le. Group:. "ill probably form the subject of a BuLt.Enx ar ticle in the near future. G2XC is to be congratula ted 0 11 his ingenuity.

G:\!Gjj. Rece ive r G roup

Further to the notes in t he last issue concerning the lack of support for t he Heceivcr Group, it can be added that experiments with ;il l forms of measuring apparalu~ fall into t he programme or this Group. It must be realised that very little experimental work can be carried oul without lhe aid of such instruments as signal generators, vah ·c volt meters, etc., yet it appears t hat few amateurs are conversant wi th t he design and operation of this apparatus. Oscilloscopes a lone would form a very interesting line for mvestigation. but at present there seems to be no rnterest at all in this most important subject.

The Group Manager would like to hear from members who would be interested in forming a group to work under the general heading of " )leasuring In~truments." This docs not imply extra hard work or extra energy ! Here is a chance to prove we really are experimenters.

The T.RF. sub-group arc engaged on many interesting problems, including R.F. regeneration,

band-,witcliing anti R.F. a mplification. ll is hoped shortly lt> publish :;orne data which wi ll be o f general inleresl.

Amongst other ilems the U. 11. F. sub-group a re studying a recc·ivt•r for ){adio Control and pushpull detection

../ 11t11111c1t1c Rtac/1011 C 011/rol The G.C.'s and G.:\l. ha,·e chscus.sed thi' problem

in L R's and art• at present t•ngaged in deciding the hesl lines of ;illack. (',5 11 F suggests the use o f tuned shunis (:;cries a nd paralle l r""ona nt c ircuits) to gradt· the outpul impedance of the R.F.

2CSD think" thal the shunt wst em would be unsatisfactory owing to the fierceness of reaction al the high frcq1wncies whcrt a low impedance , hunt would bt· necessary. Actually under the ,,hunt ,,ystem ;\ high impedance would be requi red for automatic reaction cont rol. lle further suggc"b a fixed reaction and rnriabk· shunt. and points out the need for t'.lre when attaching shunts across t he det ector owing to the danger of reel ucing the elTtcieney of t he dotecto r stage.

G6i\1F consickr' the sh unt filter wonld not work because of the 1wccssitv fo r an inverse action at the high frequency end- of the tuning range. H i,; theory is that cap.ic1tative reactanc;e would ha,·c to predomjnate on !ugh frequencies. whibt inducti ,·e rcactance would ha,·e to prc<lominak at the lowrr frequl'ncit"" The middle point would

Cosmic Notes Sunspots

A very la rge group of spots cro:.-,cd the sun 's central meridian on October 11 and 12, and a n average group on October 26 The latte r group appeared to bavc incrcast!CI rapidly in size during the <lavs preceding its C.l\l.P. Between the pa.-,.-;ages of these two groups there was a period of low sunspot activity. the spots being particula rly few on October 19 A small gronp o f ~pots crossed the sun's disc ('a rl)' an the month. having C.i\LP. October 5 . In connection with the special note i11 las l month's Cosmic Notes. it is now learn t that a big prominenct• w;is observed by Tokio Observatorr on September 10. Another large prominence was obsen·ed on September 29. while a chromospheric eruption was reportt.-<l by Canberra Ob::.cn-a torr on September 27. This was associated with a Dellinger fade-<> ut .

The Magne t ic Elem en ts The· followini; data covers the period September

25 to October 24. ::'lfagnetic storms were n.'Corded on September 27 and 28. September 30. and October I. October 7 a nd S. a nd October 24.

The Kational Bureau of Standards, Washington. n.c .. reports an ionospheric s torm on October 7 a nd 8. and sudden radio fade-outs on October 6 a t 14.50 G.:\r T and on October 10 at 19.28 G.:\I.T.

Past Data The Internationa l Astronom ical U nion's B ulletin

for the second qua rter of 19:18 is now to hand, and several items arc of interest. A very important bright chromo-.pheric eruption was observed at Zurich Observatory at 08.30 G.:\l.T. on April 15. The coincidence of this ";th the hissing phenomenon a nd Dellinger fade-out obsen·c<l on t hat date is noteworthy. (&:c T. & R. BuLL1nn:, May to July. 1938.) Active sunspot groups (associated

TIIE T. 6- R. Bl..:I l.F 11.\', :'\ovember 19:.IS

thaeforc not funct ion a t all, due to a reactive peak lie suggests as a solution utilising the clecrrosrat1' screen in the ,•alve. by feeding hac k part of tlw s ignal voltage as a D.C. voltage.

R . F. Stm:es 2171 U and G2\"0 tind that detector stage, ar.•

l'a•ilv O\"Crloaded, and rnstabi li t\· occur,, with regeneration unless a bulll·r "'Lage i~ used. They aho ,,trc"s the use of good chokes. and their effect on Scll.!C ti vi l V.

2B1H incntions that when using variable rcgc111•ration, tuning is not consis tent.

G:ir! F Tran sm itt er Group

As the main func tion of this Group is to conduct l'Xperimcnlal work in t'Onnection with tlw design and operation of transmilll'r~. it. should be app;1rcnt that membership can nnly be granted to tho'<: who posse~., a transmllllng licence. \\·e wish tcl make this point clear 111 o rder to :;ave us tlw trouble of <lcclinini.: ;a pplica tions from B. R S. members.

rt is a lso necessar~· lo point ou t that t he Group is not in t•xistence for thl• purpose of passing on information of the typt· given in " The Helprng I land "article:., neither can 1l be u,,ed a-. an Enquiry Department. The Society's Technu:al Information Hureau exists for tha t purpose.

G:iJ L.

with n11m uro11s e ruption~) arl' reported with ( .. \I.I' April G, 14, !ll, 22. ).lay :1. 10, 2 1. 2:.1, June 2. B. 11. 22, .J uly 2. Jl is nolic1:cl that the groups or C.:\I.P. J\pril 14 and )lay IO were not lh(' :«lmt• group. as oue was s1t11atcd in the Mm's nortlwrn hemisphere and the othl'I' in the :.outhem. Both these g roups caused magnetic s torms and auroral d isplays which, being 2() days apart, were assunwd al the time to be <lut• to two successive ct•11tral meridian passages of thl' same spots. T hi5 is now known to be incom·ct. The spots of C :'II.I' ,\lar JO and June 6 wcn: the same spots on succc,,iv,· rotation ~ of the sun.

l~2XC .

Book Revi ew .\ S1~1PLE GtHDE TO T1,LE\'1s10:>. By Sydney ,\

:.rosclcy a nd H . J. Barton Chapple. \Vh.Sch . O.Sc. (I Ions.), clc. ·13 pages and 13 illus t ra tions. P ublished by Sir l saac Pitman & Son~. Ltd .• London. JJrice Is. net.

The authors of this hllle booklet. who arc well known in the field of t elevision litera ture. have set out to explain to the ordinary man bow television originated, how it works and how it may develop. The dc»cription of the early days of television is almost entirely a record of Baird's activities.

The authors have succeeded in gh ·ing a descnption of the general pri11ciples of C. K receptio11 and the C.H. camera in 11 pages without confu~ing the reader with c ircuits. T he descript io11 o f modern eq uipment is a u expla na tion o f the trn 11s· mission scheme, and the type of receiver now nn the market. A chap!l•r explain:. large ~·rcen tele,·ision. a nd the conduding chapter deals '''Ith the possibilities of colour and s len.-oscopic tclev1~ion

The book is an i11lcrehling introduction to the subject for the untech11ical reader . T . P. A.

.. '

THE T. &- R. BU f. LET I .V, :\ovember 193 · 287

ON THE AIR A RUNNING COMMENTARY OF RADIO CONDITIONS FOR THE MONTH OF . . . OCTOBER, 1938

H .A.M. WHYTE ( G 6WV.)

OCTOB.El{ must han· lw<:n a month of high ionisation as till" 'kip on a ll bands was observed w be l"X<:eptionalh· long. This

rnndition i,.. \"C'IT useful for 14 >le 1kvotecs, as ,..ii;nals up lo .J,llOO miks arc ni.u;11ly :,carce and e rratic, whereas sign::1ls from fartlwr afie ld come in :it surpris ing strengths wilho11l lhc· resultant < llOl from local or semi-local ,tal1011' .\ case in 1l<>1111 was on <kcobcr 25, when Fl~.\C. 17.\.\, P I\ ',, l\A's and ZS's wt•n• lward at unu ... ual strength \11th a very quiet background. A quick lisfrn on 14 Mr. might concei,·ably hav1• gi.-C'n lltt• 1mprcs..;ion that the band was dead Taken a' a whole, the month of October cannot lw con ... 111l'rcd to have haw been reallv good for D:-. : tlw middle of the month product·cl a bad trough and weak wall'r~· signals were not ea;;y to rais1-.

Tia· 28 l\1c. band has nul b1·1•n as gum! as expcctc•d bv most of us, and tends to 11.'ntl so1111• proof to tht· r1:ar that we .ire on the dow11\1ard tn•111J of thl· suu ... pot cycle as far a, radio condition" arc conrern1·d . G2UX . howen·r, worked lll~·I AF: t his station is unlicensed in 1 londuras, bul a lway:<>Sl.', direct and a~ks tho,c contacted lCJ wail for his card. Other unusual ,talions on this band arc TG9AA and \S2LH. the lant·r \\Ork::. on the LF end of 28 and accordini:- to " QST," canb should be sent via \\'5FKX, Roi- 8 11 , Browns\"ille, Texai.. \Y6QAP and W60\· l\.(i ha\·e both been acti,·e Ill Arizona for tho~ who 'till require a contact with tha t State.

Four \V.A.S. certificate" ha\"C now ht·cn issued in C:reat Dritain : G6QS. Ci>11J, GG\\' \" a nd (;GNJ.' ha VI.' qualified and they a re hclil'Wcl to be lhc first four iu EurOJX'. G6QS's award \\,Is certainly the fin.t.

ZH2A had a short and sw.:ct li fo. lie com-mc.:nccd operations on 1.1:102 on Sepl<'mber 29 and made hislasl transmission" ilh G6W0011 October J.I . I li s lirst G contact wa,, wnh G IT and therefore this QSO would undouutedl\· rank a, the fi.r.,t bet wccn Great Britain anci° Gibraltar. OX \-C has been very acti,·e anti write::. to tell u~ he is ,·cry disappointed to learn that contact with hi:. station (a Danish salvage ship) dl>t',, not count .h Gibraltar. ll is hoped thal ZB2R will shortly he lward operated by Harry Worthington, ;1nd OX \'C is trying to interest yet another in ham radio, so those who missccl ZB2A may not haw to wa i ~ loo long (or Gihraltar. Those amateurs who workt>d " ZB2A." "ZB2AB" or "ZB2B" 111 the early part of the year will never get proof of thi:ir <JSO, and any

cont:i l't with a 1.132 outside the datl.,, mcnlionl'd ahov1• rannot r;111k as genuine'.

\\'c do nol hl.'lic,·e that \ 'Q.JCT ( llF 14 TH) ,, in l\cnya, but "»Omewlwrl· in Euru1w." he corn'" through al lhl' wrong times and with a strong ~igna l \\'hen no 1lthcr Africans arc audih lt.'. CN I AA has hecn activl' with self-cxcited C\Y again o n about 14:180, and l'J I B\" (HF l.J ) ha" h<'t'll work111~ \\".., in ;,trings, hut a few G',; managt•tl to make llwms<'h·c,. ltt•ard, including G6Hll, li\\·y and <l( J , <JSL's .irt• s;:ut to all -.tations worked, hut cant ... for him should onh' Ix- sent 1·ia tlw .\ .R .Kl.. Till' -.:tme applies for contacts \\;th l'j:lCO. ,1bo in Cura~ao Cl'IA..\, \\ho ha~ lx-L·n h·rv actl\"<' j1s-t out,.1dc thl' 11.F. edge of l .J fortunat1•h llO>-"l'''I.°' a good rcccl\'l'f and al way:- QSL's. \\\· should he· in t1• n•stcd lo lrnow if PX2D is gcnuii ll': he s tall'" he is in "('iudad ,\ntlorra." but \\'hen asked if thb wa' the nan11· of ;\ ship he assu red u ... that he had nc> l'arct ... at prl'M'nt but hoped to QSI. all cont,1cts in a month's 11111e. KA8ED (1-1300) \\\IS an u11-11su:d ~talion worked in Pa la wan J .. l'hi lippint•s, hul lhis dot"' not count as a scparah· country ! Otlwr KA'~ .1t11\·c included K.\I HI' ( l-13501. I\.\ IF(; ( 1-1320}. Box S-19, Canatcau, I\.\ I JK (l.J:IOO). c o l' .S Xa,·al Stn., Canacao .11111 I\.\ I })J. ( 1-IO:lll)

llaili cont11111,·s to oftcr 11113L ( 1-12~11), 11112.\I(' ( 14275) :tnd 1111-IAS ( 1-1400). all of \\fiom OSJ. CluJ,. h.1,., pmdult'd mcrca..-.cd actinty with CEJEE ( IH:IO), CE.J:\D (I H.JO). CE3BF (1-1370) .1't11l CE:IAJ (HF). Do not overlook \"1"2LC 111 St. Lu<'ia on 14:11 5. The operator is a \" J .. and contat ts ~i re known to have been made with G81G and c;2uH, rn11nti11g for \\'indward 1 ~. PZ I All ha' apparently come to life again 111 Suri11.u11, a111l \\' I FH t1•1J, us he i>. acti,·e 011 tilt.' llF si<k of 1-1 . GGH JI worked OX7ZL, who ~l·1•ms lo hl' ,1 permanent n·~idl'nt of Grl'<•nlantl according to lht• Call Book. bul no more ha ... been hcarcl of OX70l" thi-. month \'1'8AD ha.' pro,·ed h111isdf to lw ge11111ne and two batchl!S of card" h.1\••• been n·· ct>1wcl at RS(~l.I. Apparently the first contact with G from !his :,,tation wa:. GGGL. The hi:.lon· of Falkland 1,1a11d amateur radio sct·rn~ lo cvoh·~· round the fact that \·PsB departed for England 111 I 9:l7 and ldl l11t1 son 111 charge. Tran~miS:>1on' wert.' latcr made under the call \ 'PSD b\' R . .\lcLlrcn. om· of lhc e ngi111;crs in charge of VPC, ancl theu 111· c ha ngc•d to Vl'8AF, hul finally tlcc idecl thal \" 1'8t\ D would be the best call with which lo continue. \'1'8A(.~ is genuine. \\'1• lt>am from ZS5B\\' that he \\'Orkcd him on th1· 11 F end of

1-1 with a Tei no te, am\ tit~· <JllA i.:ivt•n wa~ .. \krccr. Grytviken ll a rbour, Soulh c;eorgia in the So~1thern Ocean. ~tail boats do nol call frequently 111 tlus remote part and anyonl' who worked lum may cxp<.'Ct tlwir rnrd t o !caw thC' island in ~o,·embcr.

ZL20U again raises llw point of certai n " rare" s tat ions who fail to ~~:-)L, and mentions Z l'2AC. CE7AA :,11Hl FASBG, hul we so often find that others ha,·e cards from such as these, therefore it is incorrect to rav the\· do not QSL at all Tbe real troubll· seems ·to be that when their interest llags thev appear to forget everythjng and do not a ttend to c:o rre,;pondcncc connected with radio. This is a pity because maximum cnjoynwnt in radio can onh· be achieved b\· collective mutual assistance throughoul the whole amateur " orld. \'R4AD has been heard on ' phone by Z1.20u, ancl will not be active again until the middle of Xo,·ember.

G3Bl worked Yl2BA and the operator appears to be new, "ith the name Eddie Bchnan. Cerb\inly t his station has been more active recent ly than ever hdore, mostly on aboul 14200-250 selfexci ted. 2AOU in jcr:.ey. C.I., product•;, ~ome unusual "catches" in OQ5AV (1-1030). CR6AI (a new one in Angola), EL2:\, active again on 1431 0, VP7NC, VQSAl, 1-1300 (Raoul Thomas, Thompson Road, Vacoas, :Mauritius). YS2LJ{ on HF14, YV8AA, Hl\2BL and H K5EE abo on HF side of 14 ;\k, On 7 )le. 2AO U heard JJU, PY, X E l .NN, K5A,\l and W5 and 6, and has now heard 158 countries , 56 being on 28 l\lc. C2DH worked VQ2;\lI 14335, OQ5AS ( 14300), Edmond De )ley, Tshlkapa' : OQ5A \ ', Derungl'. ~ \ '. :'.\., Leopoldville a nd I\A 1 A F (142-10). St ations heard incuded \ 'P9X (1-1255) and XlJSL'X (14405). G2DH righlly asks all contributors to :;tott.c the frequency of the station heard or worked, as the information is of little value wi thout such det.'\ils.

2DQS of Thurnb~-. l~ics .. ask,. if we want reports on 7, 3.5 a nd 1.7 )le. Yes, we dO-\"Cry much, as DX on t hese frequencies is greater new:. than on 0U1er bands. He reports CX I AA (LF l.J ), 111{51\IL (HF 14) anti CEIAS and ! ET. BRS33 19, aJso of Thurnby. complained that condition:. were poor, but managed lo hear CEi i\ H and 3AT a nd reports tha l LX IA Y is now on 14 :\£c. 'phone.

. All who worked YA5XX will be inlerc-,ted to hear somC' authentic Ill'"" of hi~ s tation. Operation was made in a t ent on the mountains near llerat, vibrator supply from car battery supplied the .12 Olltpul valve with a n input of ·I watt s. A list of a ll stations worked ha-; been sent to both HSGB and ARnL for confirma tion. but the operator finds it impos.~iblt· to send cards for contacts, but at his request, cards for YASXX will be held a l RSGB for him to claim them. The following G's were contacted in order: C5AN, 5ZT, 6RB, 613T, SWF, G)16B::\l, 5QY. STC, 5\\'P and 61\P. Sixty contacts were made in all and those members who whh for further details in the form of a confirmation from H.Q. should write to G6CL. YASXX ceased operation on September I and returned to t;.S.A., hut hope:. to be back m a n equally rare rnunt.ry (not Afgham:.tan this time), using the :-amc call nei.."t year. \\'e know which country thb will be, and su~gest you keep your cars well open I l

GSRL heard YN4J\B (formerly a 'v\17) on 14 and worked OY5D on 7 )le. 2DKQ at Heading reports ZD7A on 14-115; we shal l be interested to

T/JE T. 6- R. IJU).LETIN, ::\rwember 1938.

know 1£ this s tation i' real!\· in S t . I lelena. l'K6XX. a nd Zl'2AC were both received on 'phone Oil the LF side of 1-1, while l\7FST ( 14:,160) "~ts received when actuaJh· across the Bering Strait in Zone 19. lie requires i'nformation on XX7B (1-1390). GGXL appears tO be top ~corer in the \'K Zl. Senior Contest with a scon: of 3,735 poinls, while he heard VR4AU and VH..I H1\ , the lat.kr being on 14346 CW. l\A I A.'\. was received on 7 Mc. a t 20.00 on October 22. G-2:\II reminds us that 7 is sho" ; ng definite s igns of bemi;: " DX-y." !>O we shall expect >Orne interesting reports for this band.

This page is not complete without Eric Trebilcock, BF.RS l95 in Northern Australia . In four weeks he received 84 countries and following hi!. record <..:W HAC reported last month of amateur stat ions, he heard them a ll on 'phone in :1 hr!>. 26 mins. on September 21 ; the stations were : CK I AF, E 12L, PY2JC, \\'8BF, XL'Slff and \'I<2XS. The reception of YS2LR brought his country total to 16·1 a nd a card from Z~I B (Bcchuaualand) gave him 131 confirmations. lie reports that ZLIDV made over 200 contacts and VJ\2J·U:' a nd 2ADE nearly n•ached this total in the Senior \ ' K ZL Contest. 7 ~le. produced VK9G\\', G's and F's, whereas l.J :\le. Yielded OX \·c. VP.JTO. \ "P7XC, TF3C, TF5G an·d on 28 :\le., Y\'IAQ. VS6AF and two Tl's were heard. BERSl95 confirms tha t the rea l ZK IAA has not been active for some time, rn we can forget we ever hea rd " ZKIAA." He ra ises an inte resting point about hearing or working countries of which no oue has detai ls, l le maintains that il is not correct to count such as ZD9B until some definite knowledge is obtained of the authenticitv or othen•ise of some unusual call. \\'e agree entirelr. One of the purposes of this page is to attempt to show those who ;'I r!' /Jona jidc a nd those who aro nol. " Fl\6NW " recently n•portcd by TIIR should read l\6:NWF, heard frequently in ~orth Austra lia.

G3J R has changed to an Rl\25 with 370 ,. aml reports contacts with ZS3F, ZS.JAA, H 1\-IDA. h'.7E\l]I[ (14040), and \\'7 FYN in ~lonlana 011 14310. G2DH ha-; now worked 117 countries with 93 confirmations, so he should be in the DX Century Club ere long; lw raised PJ IBV. CP IAA. VS7R,\, and hNml HPIA on 'phone, \ 'P7:NU. OX7ZI. and XZ2J\R ( 1-1240). G6Gl l reports a contac t with OX7ZL on 1-1030 with a T7 note al 19.30 on October 1-1. ZC-IEB was heard on 14400 (T4) gh'ing his QTll as Hadio Stallon, ~ico~ia. Cyprus. G2GK tells us lw heard YS2LY and YS ILZ ! G8UA has had 11ews from Yl\14Al that Austria is now divided into lwo radio dis tricts having the distinctive letters " \\' " for Alpcnlande and " S " for Donaulande. G2CX \\anh to know if XUSGW 1s ex-GSGW . G6JO l heard Fl\SAA.

G5:\I~ had an interesting experiment forced upon him. He arrived home one day to find his normal bent. GG ft. end-on aerial lying on till' ground : not wis h1 ng to be off the ai r he ha~ti ly put it up off the ground (only jus t) a nd worked ZS ancl VU for the firs t time. I le had found il impossible to work tlwse par ts with the normal aerial, hut altering the 'lope just made the differenct· ZD21 l is still \'en· act1,·e and is as anxiou.; to contact ra re countries aq we a re to work him ! CX!CX, CE3AJ/ Bl", i-:GQJE. U2NC were contacted on 14 l\Ic. and W6PM.V on 7 Mc. VP4TO has bct:n having trouble with his receiver, which accounts for the large numlx•r of CQ's and small numtx-r of

' ·1

TI/£ T. cS- R. Bf . .:Ll.ETI:Y, Xo\'ember 1938.

\2SO·s. His inpul b. '.!2 watts a nd he is usually act ive belwee11 20.30-22.30 G.l\ l.T. on 14300. Our contemporary. \VGQD, tells us tl1<tt I<GT.F. is back from Wake T., bul K6Cl\::'-L is to lake his place and will operate on 14324 or 7162. Cards !>hould be sent to Larry nickev, c o P.A.A . JG\dio S tn., Wake Island. but he ,;.ill an~wer all cards when he relurns to Honolulu, as postage per card costs 20 cents by air !

GSDA with 5 watts from batteries wa~ reported to have worked XU and \'P4 on 'phone last month, uul we regret thal t his was not so- he on ly heard lhcm I New stat ions rece ived by SDA include llZ IA (14390) (obviously a fake), i\7£TS (140 10), XX7B (14400), K6PLZ (14390) (who is coming on with !kW. soon), KGLBH (14380), l\6DUA (llF 14) and VPGFA on 14050 'phone. G3CY added X U6ST and CR7AU and GSUY heard Xu·,, GTL, 6\\' A a nd 81' R. \\·e hope that X U6's han• not been injured in the recent Canton fires. G2QY reports the QRA of \.Q2G\\': 67, Die Avenue, ). uanshya. a nrl GGNF tells us that VQ3Al, T can be QSLed c/ o Box 45, L indi, Tanganyika . Gl\f6BM d ocs not agree that 220 v. D.C. mains constitutes QH P and assures us thal he C."l n use 25 watts \\;lh oa.se at this ,·oltage. He has not been active owing to illness. but had his receiver by his bed and heard WGNP0/ 1\6 ( 14025), l\HAKI 1 (the Hughes' plane) working W6l'IIQS. C5AN worked VQ2:'-lI and was given the following QRA : A. ] . :.\l iddleton, Box 235, ~'J\ana .

In Search of B.E.R.T.A.

I Domi11io11 I

Call Di~tricls Co/011ics I Total

G5HH 23 12 I 35 GSHA 22 11 3:1 GS'.\"D 22 10 32 G6ZO 20 11 3 1 G2GK 23 7 30

\ .U2A...'\' has been vcn· acti,·e and heard )!X3A (14250), ) 1X3B (14100) and worked \ ' l.:9VG. G5ZT contacted ZZ2AC at 2 1.20 G.l\l.T. on October 2, who claimed to be an American operating on the Tirriman I slands, Galapagos Archipdago. 350 watts into a rhombic were supposed to ha\'e been used a nd QSL's were requested viii W2EF. 5ZT was assured that cards would be sen t to a ll s tations worked when he returned to Boston in two months ' time. G2Y\' using 10 watt 'phone had a contact with Algiers with SS both ways on 7 )le. G3IH agrees with G:'.I6JD and docs not call " test" on 14 i\lc. but waits his ma11 . His rc:.ults show that this procedure has paid and contacts with QRP (350 v.) were made with P l\3£:'.l, X U6TL, ZE. TF and \" IC G5Hl-l worked 1'Al BC, ZE I J L and V K6ZO for new s tations.

WSACA wri tes to give us the true s tory of the mysterious " VPJT EST ." He has received a letter from one of the operators who told him lhat a;; the natives run amok occasionally and tear up the communication lines from Georgetown into the in terior, small QRP outfits are available to take care of such an emergency. \Vhen traffic is slack the}' tune these transmitters to 7 or 14 l\lc . a nd

2S9

'<ign \ 'P3TEST. Cardo should be sent via Vl'313G, .J . S. Kerr, 1, Well ington Street, Geoq;l.'town. \VS/\.CA is in Louisia11a on 14380 or 14:196 with SOO watts input, and is a 100 per cent. QSL station.

G31'S worked 38 countries 10 lus first month on the air, and both \\',\ C and \\"BE. Jlts aerial is inlcrcsting, being a 70 ft. top fed by a doublet, 16 ft . 5 in~. each half, and this doublet is ,·eriical and is in turn fed by a 72-ohm line. Rc;,ults l>peak for thcm::.eh·es. BRS1066 of Burton-on-Trent reports VP5BR, 1\(:i;\lTE, KGPDQ and X U70 1. and he has now heard 136 countries with !)5 conlirmc<.l, whi le U9AC obliged wit h a ca rd.

ff you observe any peculiar fade-out,; o r conditions of almormalitr on any band, we r.hall be plca,cd to publish details of such occurrences.

THE 28 Mc. BAND By NELLY CoRR\ . {G2YL)

TllE . genera l irnpn:s8ion a mong regular " Ten l\lclro Addicts "~!'ems lo ht' t hat condit ions las t month were not so good as those of

October, 1937. Certarnh· more DX was hc.1rd than ever before 111 the hi~tor}: of the band, and at time:. QR:\! was terrific. cspeciall r among the 'phones, but on lhe whole QRI<~ were lower, and QSB more prc,•alent than a year ago. G6DI I report-. that hi:. graph of the hight'ot frequency heard daily i::. keeping Wl'll below that of 1937, and it seem~ quill" possible that we have already passed the peak of 28 l\Lc. conditions i11 t he prescu t sola r eye)(:. T he impression a casual li , lcncr on lhe band gels is lh:n it is "all \\" 'phone>," but BRS3179 proved thal there is plenty of activity a ll o,·er the world hr logging 90 different DX :.tat ionsduriogthe month, exclusive of North America and Europe.

Altogether s tations were heard from 65 countric,,, and all continents were audible on October 2, 9. 15, 16, IS, 19, 22, 23, 24, 29 and 30. G6Dl I wa,, \V.A .C. on the 9 th and 23rd, and G2DH worked all continen t:> except Africa ou t he 9 th. Oceanic s ignals came through daily £rom October 13-24 anti on five other days, a nd incl11tlcd 23 Australians in \'1<2, 3, 4, 5 and 6. Station" in ZL2 were heard by G6DH a nd G6YL, and ZLICC and KAL\P b,· BHS3179. On October 6, 18.30- 19.30 C.~l.T., 'several 1<6 'phones were audible at good s trength, viz. : K6:'-LVV, worked b,· G2PL, KG:-.CVX worked by G60H, and K6BAZ ht•nrd b,· BRS3179. PI\ 1 \ ' Y wns heard on seven dn\'s after the middle o! the 1nonth, a nd was worl<t'ZI on 'phone by C6D ll on October 16.

Stations in Asia, heard on 19 or more day:;, included VU2AX, who had ten QSOs with C60H during the month, and Vt:2DR. 2ED. 2EU, 2FS. 2FV and 2FZ. G6Dl 1 made First Contact with Burma when he worked XZ2£X, and later XZ20X, on 'phone on October 20; XZ20Y was al..o heard aclive. Other interesting signals were JIS IBJ, heard by BRS3179 ; j2CD, heard by 2DQS: VSGAF, worked by G5ZT. G2WS a nd G6l<S: a nd VS6AG, heard by C6Q7.. About 40 st ations in Africa, the majority of whom used 'phone, were heard on al least 24 da\'s , from CX, CR7, FA. FB, SU, VQ2, VQ3. ZE, ZS l, 2, 4, 5 and 6. CR7AG was reported active for the first time by G6YL.

North Americans were audible on every day in the month except October I. 7, 17 and 27. G5Ll

'.?90

\\Orkcd all \\' di~trict,; on ' phOrtl' on Octohl'r -I, a nd G6l<S 1•omplctcd his \ V.B.E. hy \JSO's ll'it h \ ' E5, and worked all \\' dist ric ts except t111· St h on 1 "·on Octob1·r 1$. \\'mobile -.tations IO!(!(l'd by BHS31 79 \\l're \\'9BllP, a new -.hip ,,1atio11, a nd \\'2CQB. ai rcraft owr :\ew York.

Signals from Central America and tlw \\'est Indies wen· al-;o heard nearh· even· d:I\·, and rndude<l 24 -.tat ions 111 C\I, F)( Ill I, HI. I iH. K-1 , 1\5, TG. TI. \' P6 and \ 'P9. 1-117(; wa-. tlw most rnnsisten t s ignal from this parl nf the world, and was heard on at lcas l 22 days. As in North a nd Cl'ntra l America, 'phones predominated in the South, and included 2 dozen or more :-tation~ in CE. CX . !IC HK, Lll. PY, \ ' 1'3 and Y\' .

Signals frcim East ern Europe were ofll'll up to SS, and on a few day:. :.kip was short cnoui:h to "nable Ds. F,,, II Bs, etc., to get through at good ,..tr.•ngth. Pre-skip Mgnals from (;)I, G\\', P.I, O): anti PA wrrc also audible in England on many oc(asions, s tations about 100 to 200 mile" away ,omctimes hcing hl'artl up to SG. Th" " hiss" was heard on October 11, 14 and 17 for short pl·riods.

)Ian,· thanks to G2l>1 1, 2XC. 5ZT, llD l I, 6 KS, H<JZ. GTG. GYL, 2DQS. BRS25, :1003, :1179, for th('ir useful n·ports. Th(' latest date for rt't'l•i\'ing n·ports is tlw 2Sth of the month, and not tlw ISth, a' published (a,.t month through a tnbprtnt

THE 56 Mc. BAND BY J . .\I. I<. Sn rox, B.S1.:. (G\\'2:\G).

O\\'J)\(; to the d1ange in tlir<'Ction of thc;;c

noH·s and the fan that none wer<' puhlish.cd in thl' Scptcmlx:r issue, tlwr<' arc a number

of report' lo,·cring July, August and Scph'mber to Ill' dealt wilh thi:. month. Front th <: I )(·,·ember bsm· on, however, it i~ hoped that t his feature will revert lo normal and will consi,;t of rc·ports of activity lO\'t'ring the pre\'iou~ mont h.

Contest Re1ults from U .S.A. \\'9~Y s,·ntls in his eighth and ninth monthly

n·port:s for .\ugu:.t and September Aui:u,t proved .1 \'l'r\" bad month for him, for no DX ~lal1011' were hl'arci or worked and no D X r<>port~ rcc,•1\'l'<I. He mis,c<l thirteen days of operatfon owing tn holiuays, hut it appears the month was very poor. He is hoping for real DX ! now the " clome,;t ic " DX is owr. and will be 0 11 at 14.00 (;.:.1.T .. 18. 15 and 19. 15 G."'.\l.T., on weck-tlavs. lit- will al'o transmit on Sundays be tween IS.00 and 17.00 (;,:\LT .. \\hich is the hcst time for OX . lie i' contemplating rom<' changes to the transmitlt'r and n·cch·er and hope~ to work G in ~o,·ember. In s.·ptcmbcr he w:1s transmitting c\'cry day but three, with no DX rc•sulti-.

Brltl1h Reports There a rc two re1x1rts from GSLY who ha, pro,·ed

,, \ 'cry consistent con trihutor to these noll's. dc,;pite thl' J{andicap of bring in a locality whcrl' 56 '.\le. a rtivitv seems vcrv low indeed. This s tation has one faithful li~tcnc·r, 21H lT, eight milrs away, who kl'rps a con,,tant ch<•ck (>n ttic 1ran,mb,.ions. From .\ugust 2 I<> 5 only 21H"'f's. report' w<·r .. rt·le1 ,·ed. hut G20D and 5N F \H're heard on the 5th and Hth, witii f\'.\IC (?) on 'phone on the (ith :<bo. On

TH£ T. G- R. BULLET/ .\", ;\o,·ember 1938.

.\ugu:.t 7, S.\lG, 6X.\l and 5.\IAP were heard and ii~\IAI ' was worked . C20D was heard at S2 011

August S. with \'l• ry t huncl1·ry rain and poor con· ditions. Augusi !J, 10 and 11 were dead except for 20D. hut condition~ impro\'(•d on the 12th, 13th. and I-Ith with 20D, 5:\F, HX)£ a nd SDF who \\;h

worked with deep QSH on 81. Y on the four-w:l\'t' aerial, hul no QSB \\)l<'n 81.Y was using the half"·nvc: •H·rial.

.\ ugu,..l 1-1, 15 and 1tl pro\'l'd blank. but 5:\F was contac ted on lhe I:ith aml 19ll>. From tlu,;n to the 1•nd of the month l'Ondi l ions were av.:ragc, wi th no new contacts. 81.\' comments that tlw band was \'ery de,·oid of -.ign:il:< during August aud quc,tion,; whether this wa' clue to holiday-, or " ~hort-skip " lengthening 0111.

Activities at this ~tat 1011 were curtailed on September 1-1, dur to cmt•rgl•ncy crisis work. but the month was q•ry an·r,1g1• The usual statmn' were heard and worked, mcluding GGX)I, 5:-\ F, 5HD, a nd 5:\lAI'. but a good report: was receivl'll fro m <;Hos. SuSSl'X. who r<·edved SL\ ' at 54B. A que<'r plll'nomcnon occurn·d in October . 21HJT has alwa\·~ Ileen :iblr to n·cl'i,·e 81.Y ,·en· well . using pr:lctically no aeria l, hut at 2 1.00, ori Oct11-bcr :l: at 2:1.00 on Octohl•r 5, and at 15. 15 on Octob{'r 8, no signals were r{'cei \'ed. Signab n·· appcan·cl at 19.00 on Octolxr 11. Both rcce1n·r and transmitter \\ere Chl•Ckl'd anti found to h1· working normall~·. Perhap,, this will be anothrr myst.-ry of the "Cindcn•lla " band !

\\'hill· on the subjec t of my' tl'ries, here 's a no tlwr l GJ8TS has sent in an :t('t01111t of events whil'h happl'lll'd on Sl'pt1•111ber 24. He was portahll'. with c;1SSJ. on Scrabo 'l\rncr, ;\ewtownards, Co. Down, and so was G81.l I' in the Lal<c District. The two station,, \\'t•re about 90 miles apart, wi t h no lllll'n·eninf! natural oh-.tacles, yet nc1tlwr 'tatmn rt•cei,·ed the other' ~umerou:. report- on thb day g:n·e bad conclit1011:.. Indeed, the I ri'h station (011ld not contac t a :, lation s ix miles aw;\\', while· 8U P could not <..)SO :t station three 111il(., away. A listem•r':, report from Bolton gav<' till' usual S9 police signals a' SS. Did anyon<· l'b" notic1• particularly bad condiiions on this date f

A \'l·ry interc~ting anrl h·ngthy account, both of hi!> station and acti\'itiC':-, ha~ been recei\'ed from '.?BIL (l'x-Blt. 3:l22). Although there is too mud1 detail to mcludc here, a ft•\\ " l1igh-lights ' will Ix· set out . From April to thl· second week in Scptc111-ber, on Sundays, he was portable at various places in lhl· South Sussc.-.: Down~. with 2DFG and 2])(;1{. I t was noticed that sign:ils were affected hy llw nature of the soil. \ 'arrous aeria ls were tril'cl, being 111ai 1lly of tlw \\'8J 1\, Rt'inartz Rotary H1•am. folrl<'cl tloublet, e tc .. types.

At: ti\'ity in April <tnd )lay seemed confined to GU\ ",\ , 211G, 2'.\IG :ind 8s1.; At this period the'"' -,cation., were reCl'i\'ed far helter than in an} ,tu -ceedin!( month "hen activily was g reat er.

Activity in June was al a minimum. KF.D. conditions were poor but ve ry many semi-loca l sta t ion~ were rccci\'ed. 1\lthough Sunday, July JO. wa~ a had day climatically. with hea.vr rain a111I a Scotch mist giving visibility of only ten ya rcl s, conditions werr excellent. J l appears t hat moisture and 1111,,t do not absorb 56 )le. wa\'es ~ An extr«ordinary number of s tation ... was heard at remarkable s ignal strength. \'cry ft>w fell below S7 and many wcr(' S8 , 9. Condition" were again good 011

TJ/E T . l-;,. U. llULl.ETI.\', :"\OVl'll1hcr 1938.

July 24 and lhe hii.•i11g noi,1· ''a ' )l('ard 011 Juh' 3 1 ;it thr ~a mc time that (;nYJ. lward 11 on 5H ~le. :u1d VU2A1' on 28 ~le. Thl' onlv s tation heard' was <:CWU.

S1•ptl0 mhe r 9, 10, 11 saw an at11·111pl to maintain s ixty hou~:; · conti1111011" lbll'ning on Ditc hl ing Beacon. J ~xcept for Olll' p1·riod or s l<•(•pincss th1· atlc'mpt .wa, we ll carricd oul ! Sl·pkmh .. r ~) g'1v<: com rn ~·rcta l harmtinics all(l 8 1\ %. who pron·d thC' lx:sl ,.1g11al o f the whole p1· riod (i X :.1 wa" heard 111 QSO with 111'0 and HFL (Camhs.) was heard on low pow(·r at S5. On Sepll•mlwr IO 110 s tation lOll1ml0 11ccd testing unttl IH.07, whrn 513\' wa, hcard. \ 'an ou '> tests \\ Crc heard from then on l~1~t al 20.00 thl' band wa.., quitt• den,,• with ,ignab.. (•l·O was hc:1rd from 2:1. JS on with monoto nou" regularity. Ac tivity pcrsi,11·d 1111111 02 O:l but from 02.00 to 02 :rn a l.ivervool poh<:« transmitter '"" lll'ard. 6FO was again rl'C<'in•d in the morning .1ncl s<1 "a" 5JU a nd 5HDI'. who wa-. al Oxford.

On Augus t 8 an F8 c;dl (full call uniden tified ) '~a' ~eceivcd calli11g CQ. and this coincided with a r~~l' 111 mush le vel similar to th t• hissing r10ist·. (.;,~JA wa-. the 1110,t i:on ~islt'nt portahlc s tation during the ,,ummcr. I le 'ccnu:c l lo hl' ac ti\·e nearh· l' \'ery wcl'k-encJ . The writer 11111, l i.i ncl're h- thank 2HIL for thi-, splendid l·tforl a nd 1, 'llT<' tha

0

t Ill' will be willing to gin: dctailcci Tl'llOrts Lo anv -. tation anterl•-.tcd m his ~ummer lbkmni:. The numl•ro11:" tat10n-. hs tcd in hili report ca11110L l>t: !{l\'l'n Jwre on .1u·ount o f -.pace hnut.llion.

ll t•n· arc t\\O notl" from BHS2<i0 1 (111 Sepkm-ber :111 .1t 21 .30 on 59 \k ,, i:omml·rdal "'" hl·ard 'ending information alJout till' l11L1•rn,1t1onal sil11at1on. .:"\o call ~,-a:, i::h·~·n .uul Lill' -.1g11al "'1' 567. On .October JG con~ht101h \\ e rt· n·n· c1m·cr. :\II :. lat10~;, '~ere except1011a lh· '"'"k up to 1:.1 00, wll<·u <L rapid 1mprovemc11t began. Tlll're mu-,t ha,•e been a local change 111 t·o11dit1011,, for other :. Lat1on~ n·t:orded an inc rea:.c· in OH I\ . ( ;51 J.\ was onh· S6, \\~ll~e t~sually S9 plu-., • ancl .'iUY, 1i-t1ally 589. "•I' <'1 48 .. rhcrt.' appcarl•d \0 ht• no dimatic OT • nmosphcnc t:hange, to .1tn111111 for tla· ,ncJden tlllJHO\'ement

( ,l}I)} ) sc:nd, a n llltCrl·,1111a.: .tllOllll t of gear .111d ~hl·dules .~nd abo snmt• , . .,T\. 111tc•r .. , 1111g c:omm(•llh. ." 1th a \'en· t11w r1·1·1°1\'l'T lw t:<ln d<·1x·nd m~ um,1-.tl'nt grouud-\\,t\'t• n·t:1·ptmn up to 611 111111•, I h• want, to kno" ol C'.1111hridg1· ac-li\'it,· 11? rnmplek l~i" c:.ir~lc ~f r.1<hat1on. On s .. p11·mhcr I .I lw was ~2SO h~27. (hll mtl<'s) al 21.50 a ucl hea rd 111111 at 20.:10 on So.:pt1·111lwr l.'i . hut was not h t·a n l. On S<"ptcmhcr 14 he wa:- part (>SO "ith 21\ 0 (80 111il1:s) and 2H G (65 mill·,). cin S,·pt l·111bvr ;m, t~·st111g a new beam, he he;lTll 5 l!Y at H:l 'phom-. l·rom then to October 2-1 hl' lll'arcl 2 11 C. 51\Y 2~.C' (<2SO. ~o mil~~). Ii\' :\. (HO m1ko,, SS) and Ill.I'. (hO n11J,•s, S4). );o one w11h111 :m miles of HUH h an1vc: o n ltve ! c.:<il> l I tl11nk' J>X 1·o nL:'ICt:. !:11lwr re mo te thi ,., }'l0.1r Thl' p1•ak "·h in 1936-37. J he upper frt•quenly h1111t 1' lOn,ull'rabh· clo wn on the same pl·riod J;i-l y1·ar I ~i-t Octoh~·r w 1· had . tln·ady n:al·ht.>d .18 ~le, hut 1h1, month ha\'l' ban·ly IOUChl'll :18 )le. ! .. G211G sends i11 :-<>Ill<' 11111•n .... tini: o l>-crva l1<>ns. I tu: only days he ob,,·rvcd c:c)tttltl ions w impm\'C

were July 2 and 19. On Jul r 2 he was h1·ant in 1113 and h:mnonics of J I Bl I,

0

l>l\JI 11nd ICE were Jogged. On July 19 twu co 1n11w n;ia l harmonics w ere heard bctwcl'n 09.55 a ncl 10.:IO H.S.T . at

291

S5 t;. 01w wa' hclie,·ed to hl' I BE. but no calls were given. Conditions fo r HU milt•s' working W\'rt• hetll•r in July. and thr best night for short..;kip workiLlg wa ' July 6 . :->0111c thirty c.;•s wcro lu•arcl working on the barn.I .

Suuetted Schedule Scheme Tiu· wr itl'r rnns t record his co111plell' d b:1ppo i11 t -

111e11L with tit,, :-.up1x1rl accorclcd 10 thb sche me. Eigh t stations, main ly rccei\'ing. ha\'c sent support for the schcmo.:. It would he redundant to outline the adva 11tag1·s of such a scheme which would, at lca,,1. ,.11,nre thnt a s tation could hope for some acLi,·ity o n the band when he wished to operate. I It• b ve n · do ubtful whethe r to continue but doc,; not like to cli~appoint those who ha, ·e \Hittcn in,"° lw will st•l out the »Chcme herc. P)('a,,,• M'nd the following cl1•taiJ,.., toge ther with a halfp,•1111\· ... tamp. hy :\owmhcr 25. (a ) Xame, call, Q l<.A. (b) Exact ,chcclule timcs. or approximate a nd likely lime:. wtwn tra1h1111,,ion or reception can takc place. (r) Typ<' of transmissions (receptio n), e.g .. plain C. \\'.. I .C. \\'., ' phone, and also whether these signals will hl· frc11u1·ncy stabilised o r othcrwbc. (11) I >1•taib (precbe) as to whethe r thest• tr:tns m is,wn.., (n•ccption) ";11 be beamed, or from a rolatinj:( array, or from a n omni-direc tio nal a.:rial. (e) \\.lwthl' r rc110rb a rc required and where the \· ,..J10ulcl be 'ent (cltrct:L o r t•ia R.S.G. B.). All member, inter~·,Lt•<I who wi:.h for a copy of the circular (if enough ath\\er to warrant ih ci rculatio n), but "ho havo.: not rontributcd to it, an• a.,k<'cl to ,..end s tamp and <]R\ \\'c wonder if there a rc fifty ,.,tat1C1n- 111\l'r1•,L<'tl enough in 56 ~k. to ,..upport tJu-.. ~<. hcnh .. ' ?

British Isles C.alls Heard Al .-e11 by CG ll'Q. July 28 lo August 22 :-600 111., .\'.£. IJa11a111a : g5nd (569). Canal Zone:

g2xn (589), g2,•d (569), 2pu (56f) , 2xv (57f), 2oc (56f), 2xy (57£), 5nd (559), 5rv (57£), 6vr (58f) • 6wy (569). 6gh (579), 8ms (559), Smj (58f). 400 111 ..

.\' . C11ba JI'. ! .: g5td (57f). 400 m .. .\'.£.Panama : g5tg (569), Gks (569). Soc (568). 200 111 .. II'. Panama : g6ux (56f), 6wx (57f), 6"T (58f), &I\' (589). 200 111 ..

S.S II '. San Fra11cisco: g8pl (559), Sqz (559). .·I beam San Francisco: g2km (579), 51i (563). 100 111, 111) Orrgan Coast: g2oc (563). 3ah (569). 3hs (569). 3mg (567), 3gr (558). g l5wd (579), 5rv (579). ;'iii (449). Gks (579), Gkp (559). Gzn (559), 6 me (564). 8hh (578). Sww (579). S. of Jlanro111:er : g2up (559), :.lbs (5Ci9), Siv (559). 51p (549), 5uy (549), 5wp (589), 5my (579), 5qa (569), Sli (566), 5il (579), gm6h1. (559), Sal (559), Sga (559), Sww (569). II '. of I 't111ro111·1·r : g5iv (558). .\'. of 1 ·a11co11ver : g2hx (-149), Sli (566). 6qx (579), 61b (4..J9), Gtd (449), Spl (-149 ). Englewood, 1 ·a11co 11l't•r: g2cy (548), g w3qn (559), Gbt (449).

The al>o,·e list was sent in b\· G2CD, who will be glad to !;J\'C further detail;, if° a :,tamp is enclosed with the t'nquiry .

* * * Vl'..JTO, l'ointc·a- Picrrc , Trinidau. B.\\' . I.

August 3 1 to September 30, 1938 : (;2ik, 2iu, 21h, 21k, 2011, 2pn, 3hh, :.lih, 5an, 5km,

5mv, ;'imw, Sns, 5sg, 5s r, Ssu, Sto, 5yu, 5zt, Gbi , gmGhz, g6ko, Gku, Gqx, 6td, Gyp. Sax, Sdv, Sfi, l:lgo. Sii, ll ik, Sjs, Sun, Swc.

292 THE T . .S. R. Bi'LLETIS, )>o,·ember 193 '.

The B.E.R. U. Contests, 1939

T II E Ruic:. for 1 he 19:l9 Contc:.t which appear

111 this 1si.ue. present no change >O far as :.coring is concerned. the only major altera.

t Hlll hcmg the· introduction of a ... ix figure serial number scheme for the purpose of claiming a wntact The arrangenl<'nt 1s already familiar to nHht or our members and consi..,h of the R.S.T. n·porl <lll the other stat ion's signals with the .1ddit1on or three figures indicatmg the number of th1• wntact. Thus 569004 means H5 56 T9 and the 1·111 rant's fourth contact in the conte:.t.

Thc outstanding change b m connection with the 1lall·s :111d duration of the t\\O sections of the ConH•st. For >Ome time it ha:. been felt that it is 11nfa1r 10, and unpopular with, th<' rest of the world !or tlw Britii-h Empire to monopolbe four week· l'll!b during the height of the J>:X !iC:l!>On. It is also a fact that the wcc.:k-end s\':ll<'m tends to favour tlw high-power station, or al any rate 1hos1· who manage to work certain parts of the ":orld whil h only come in for a very ~hort time each day.

H igh Spots of the 1939 B .E.R .U. Contest s

I. :>ERlAL ~t.::\IBERS WILL DE t;SED. 2. SE:\' l OR :\)l'D J U}\IQH COXTESTS

\\'JLLRl..i~ OVER TWO 4-DA Y PERIODS (96 l!OURS).

3. OPERATrnG TDIE lN EACll CO);TEST Wll.l.13£ LJ:\llTED TO 30 HOURS.

4. EXTRJ\ NTS IX TI IE RECEPTION EVEl\T WJLL HE Ll:i\IITED TO 15 ll OURS' LISTEl\INC LN TJIE SENIOR A='D J U~lOR TRANS:\llTTJXG COX· TESTS (TOTAL 30 HOURS).

5. EXTRIES )lvST BE POSTEi) XOT 1.ATER Tl-IAX SE\'EX D:\ YS AFTER EACH COXTEST FlXISI I ES.

Further. it is very much of an endurance test, involving continuous operation over 2·1 hours at a tinw of the year when, for many, such strain is hardly relished !

The H.S.G.B .. after considerable discussion and sift ing of the views of a largo nu mber of members, have decided to try a schem.; which is a modification o( the American DX Contest plan, namely. a Contest period of several <lays with an operating tinw limit. Each of the two Transmitting Contest s will t'Xtend over 96 hour" and competitors may 01wratc their stations during 1·ach ~cction for not more than 30 hours. This limit of 30 hours will giw everyone a chance to pick his own peak periods whc.:n opportunities for scoring arc greatest. The time may be made up in any way conwnient to the individual operator, and c;ich spell must be recorded on t he log sheet, in accordance wiih the l~uk'~.

\Vith regard 10 the Receiving Conte8t, a compel ilor will be a llowccl to select his opcrat ing periorl in the same mannC'r, hut. his total must be compost'd of not more than 15 hours' listening

during the Senior Transmitting Contest and not more than 15 hours during the Junior.

Although the above plan is in the nature or an experiment, it is thought to embody the advantages of week-end and period contest., whilst avoiding the difficulties of both.

Xow that the Empire Air )fail :.cheme i~ an establi~hcd fact, the Contest closing dates ha,·e been advanced. It will be seen from the rules that aU entry forms must bear a post mark of not later than seven da ,.s after the close of each contest, and no entry \\;II be accepted later than )larch 20, 1939. Competitors who disregard this ruling or who fail to complete the analysis form will be dis· qualified. Thb dcci;;ion will be most rigidly adhered to. An entrant who by his own carelessness finds bimsclr disqualified will have only bjmsel( to thank.

It will be noted that the Contact Serial :\'umbers have b1•cn printed on the entry form, and take the place of the column hitherto designated "Contact ~o."

The usual appeal i;; made for care in making out the entry form;,. After all our efforts at pcr::.uasion, some of the entries arc often a disgrace and arc scarcely legible. 11 a competitor is interested in his entry, the lea:.t he can do is to prepare it in a neat and orderly manner.

We again appeal to the sporting ;,piril of the telephony enthusiasts to limit their activities to a minimum during the period of the contests, cs· pccially in ,·iew or the fact that they will now ext end over two week-ends instead of four. \Ve should also like to ask everyone to send in a log, however few the contacts made, as this is invaluable for checking purposes.

Certain stations have, in the past, refused to work contacts with a zone when once they have reached the "one point per contact" stage. Whilst this is manifest!\• unfair to the other stations in that zone. it is ·also a very um,;sc procedure to adopt, !or it often happens that a few " single point contac~;-" ha,·e ~ade the difference between a place and also ran.

The best of DX tO everyone and may all the la,·crs and cosmic ·• whatnots ·· combine with the good behaviour of King Sol to produce real bumper conditions <In ring the Contest.

A.O.'.\!.

Southend and D istrict Radio and Scientific Society

)[r. J. :\f. ·wacson (G6CT ), hon. i.ecretary of the above ;,ociety, informs us that a new venue has been obtained for their meetings. This is situated in Southend High Street, \\;thin a hundred yard,., of the terminus. to which transport comes from all o ,·er Essex.

Some 50 members and friend s recently att ended a very successful all-night field meeting. ·1:he transmitter was concealed in a ditch near extensive woods at \Voodham \\Taltcr, and was remotely controll<:d from :t tent in the middle of the wood. ~lr. L . J>ugll (2BNR), the only successful COl\)pctitor, found the t ra nsmitter in th ree hours a ml 23 minutes.

THE T. '5- R. nc;I.LE1 l.\", .:'\m·cmber 1938.

The R.A.F. Civilian Wireless Reserve

/11 !"lei<' o; the 111/ernt being slior.n1 m tliis Resert·e. we lie1.-e requr,tetl tlit .ltr .ll 1111stry to supply us eaclt month wit It official injomurtio11 ru11re111i11;: 1/s progress.

AS a preh1111n.iry lO the further extension of local training, tl was decided early in October to appoint twelve Regional ControUers with

stations located rn the following :uea.~ :-G ro up A ( Reelona l Controllers)

Berkshire. Fifc:;hin:. Blackhealh . Glasgow. Hreconshire. 1 lcrlforclshirc. Cheshire. Kent. Devonshire Lcicl•skrshire.

Yorkshir.., . The Controller:.. mo~t of \\liom are R.S.G.ll .

:members specially rccommllnded by that Societr.

~---.,, . ' :,..;..--

The R .A.F. Ciuilian Wirele•• Re•ervc

Bad•c·

will cventuallv be allotted control' of 20 o r 111 o r e C . \ V. R . :o.tations within their region. Their stations will operate on a Xo. 2 frequency to the ~o. 1 or 2-lain Control frequency, and they will be responsible for maintenance of the .:\o. I frequency for exercises "ith the main station, which " for the moment located at Cranwell, Lincolnshire. The :Ko. :! frequency will be used for inter-communication between l{cg1onal Cont ro I 't.1 l tons, and sub

stations. Thu~ a \ \\".R. \\" T relay system \\ill be organised throughout the British Isles.

Group A communication tests and exercises on a frequency of 2580 kc. have bc<·n carried ou t satisfaclorily with t he R.A.F. :\lain Control s talion , . an<l the abilit.y of t he membl'rs taking part in the -oxcrciscs ha~ been so good that. the main station has frequently been hear<l working at full speed in order to compck with the standard of transmission and reception dc,·cloped.

G rou11 B A second group of s tations (defined as Group B)

has now been hcing organised, and their tra ining <:ommcnced on )lovcmbcr 7. The allotment of Croup B is intended to cover art•as at present not included Ill lhe Group A org:111i;.ation.

Ewperimental Sect.Jon An Expcnnwntal Section ts 111 process of actl\'l"

formation. C \\' H. member-. arc being carefully selected for thl•tr ability and c·xperience, and a small efficient. nucleus is already co-operating. The programnw of activities b modest. at present, but the mcmlwr-, concl·rnNI an· already concen-

trating on >.ome prelim111ary re,earch work. :'lluch depend-. upon lhe results subuutted as to what extent further co-operation with the Signals Technical Dcparlments will dc,·clop. All members of the Experimental Section must be competent. W/ f operators.

A ir Mi nistry Station It is un(krstood lhat the installation of a C.W.R.

s tation at the Air Ministry is almost complete. and that operation will commence a.'\ i:.oon as members of the Experimental Section have solved local in terference problems.

Bad1oa Badges an: now ready for issue ; each hadgc is

numbered upon the back and is of a button-hole type to wear in the lapel of lhc coat. The design, which i; illustrated. represents a lwo bladed axe clea\'ing ~pace: with J lcrtzian waves radiaiing outwards.

Regional Controller Badge, will carry the d1;tinctive letter ·· C," whilst lkµuty Controllers will be identified by the letters "U.C." Jn both cases the additional letters arc to be superimposed on the top of the badge.

The Executi,·c of the C \\".H. ha,·e already been asked if members of the Rescn·e could man and control a "cries of mobile Auxiliarv Sen-ice station~ at ,·ariou,., poinb around ilw llritbh Isle,,. Although the training is in its carliesl stages the progress made ju~tifies the statement that the Reserve o rganisation wi ll he able to takl' over such a scheme.

Golders Green and Hendon Radio Scientific Society

The following lectures h:wl' been arranged by the above Society : :Nov. 9.- Tclevision Transmitling F.quipment, by

11 . A. l\'l. Cladc (GHOT) . 2:.J .- Short Waves, by .E. L. Gardiner

(GGGR). Dec. 1-1 .. ll igh Fidelity Heprnduction, by P. G. A.

Voigt. )feetings take place on the second and fourth

Wednesday evenings in each month at the Regal Cinema, Finchlcy Road. '.\lemh<'rs of the R.S.C.B. arc always welcomed.

" P hysical Properties of Sun Spots 11

:\lr. D . Tomlin. of Shellteld, has kindly pointed out that the intensity of the earth's horizontal field is . 18 g:rn~-. instead of 1.8 gauss, ~ quoted by Mr. Baldwin, 2CBL, the author of the above article, published in our last issue. '.\Jr. Tomlin also suggests that it is more academically correct lo use the l<'rm "Oerst ed unit " instead of "Gauss."

294

l.E.E. M eeting Tia- nt·'t London llll'l'llll:,: "Ill I~ hdho11es c~ C11/1//'$, Utl .. will d l'li,•cr a ll°C\11rc 011 lfocent \':ih·c I lt·n·lopmcnts.

The I. E I~. \\'ill be o!X'n from 5 p.m. Tt'.l will be -ern·d fr<'l' of charge from tl pm .. ancl 1111· lecture \I Ill l'Ollllllt'lll l• at 6.-15 j) Ill

It 1' hoped 1hat good ' "PJlOrt will Ix· :.:1,·en to t 111- llH'l'l lllg

Honorari ums Thl• Counl'il ha\'C pll•a,ur<· in announlmJ: that

Honora1111ni- ha\'e bct·n a\l.1rckd to thl' followin~ nwmlx•r, "ho co11tr1bull'd out-.rnndm1' ar ticle:-. to \ 'olt1m1· t:l ol THE T . & ({, IW1.1.1fflZ':

.llr . .f . H. lfryden (2HOI.) "Hcmot e Control by Hadio." pai.w i 5, A ugust, l!l:li.

Jfr. II .. /. .l/ . Clark (t ;GOT). " Tlw l{edudion of lnterl1·n•nc1• tluc to Hadiation of Third I larmonics." pag1 2:15, :-\o , ·ember, 19:1i

.\/1. F 11' Garnefl (G6X L) .. Exp1•n1·nC«' with a Simpk• J>m·Llin: Aerial ," pag1· :155. Ja nuary, 1938.

.\fr. I . II . C/ar/1 (2Bl HI ·· :\ H<'vll'" of ;\lulti\ 'alve Ama11·nr T.R . F. l<t·t1· iv1·r,. " page• tlH'.!, June, t9:JS.

.\fr 11' // . • ·J/le11 (G'.!l'J J " Four Y1 .. 1r-. .111d Xo Signals," pai;:t· 6 'S, J u1w, HJ:IS

District 18 Representat ion Due lo prc~sure of private business, Mr. \V. A.

Clark (G5FV) has tendered his res ignat ion from t he position of District 11:1 H«prcscntative. T his opporlunily is taken or 1hankin~ ) lr . nark for his past service,,,

It is hoprd to appoint a >t1Cc1·s-or at a n 1•:1rlydate.

8.E.R.U Contest Con tacts A New Service to Members

,i. ., an 1•xpcriment, Council ha,·e agreed to a llow mcmhcr,, who ha,·c been unable to obt:un confirmat ion (in the form of <lSL cards) of \'Ontacts made \\'ith British E mpire :< la tions durin!( recent l3.E.n .u. Contests to apply 10 Hcadqut1rlc rs for a ccrl if1cale.

The following condi t ions go,·crn t his a rrangement:-

1. ) !embers ma\· only apply for confirmation

T I/£ T. 6- R. IJ C LLET /.\', ~<wembcr Hl:J8.

from slations 111 Dominion D1,1ntt" and C'uloml·s 1rom "hich th1•\' ha\'e had no prt'\'ious QSI..

'..! )!embers 1111hl them~cl\'cs ascertain, hy examining th1· rnntt-,,t rC'pon. I h,1.t an cnt rr wa:. :1ccepktl hr tht • Society frt>m 1ht• overseas s ta t ion ronccrnt•d.

:1, )[embers 11\11,l prepare a t':lrcl \\'Ordccl in lhr following manm-r:

" Tiu, 1, to confirm that \'Our st.a11011 "a" 111 con1.111 \I Ith (name of .. 1:11ion) at ........ . G.)l.T ..... .... .... 193 ...... \\ht·n your signals were n ·cord1•tl on his 13.E . H. I ' Contest loi; as RST ..... . "

Thi,, po,,tcanl 11111-.1 be self-addre .. st•d a nd st,1111p1"<I aml for" ard1:d u11d1:r co,·er tu 1lw Sccrctarr. who \\Ill, if the cont.Ill i:, confimll-d. '1gn theccrtificalt:

The po,.\l.ird "ill additionallr carry an impression o r lht· Society 's :,cal.

-1 . Contacts rn11 onh· bt· chet•kt:<I back fvr :~ pcriocl of l\\'() )'(':I I'», e:g .• during rn:is a mcmln: r m:ty ask for conl;ids made in till• 19:17 a nd 19:18 Contests to I.Jc tht·cked.

R.S.G.B. Slow M orse P ractices Details ap1war hdow of th<' i;low morse practit.t·~

ort;aniscd by the Society for tho:.e mcmlX'rs wi:.l11ng to learn or improve their code. As usual. tt·»t mal ic r will be taken from recent issues or the T & R 131.'LLl·.n:-:. The page number a nd month o l 1 ..... ue \\ill he 1(1 \'en a t lhe <'IHI or each k:.t IH' tdc·phony. A 1dcphony announcement \\'ill al;.o he gi\'cn at tht• commencement or each tc' t to "''i:.l those in tcre:.l1•d in tuning in lh1· sending :, tation. I l i:. c mphas ist·d that reports wi ll he apprt·cialt·d :Lnd arc clcs i red i 11 o rder to ;1:,ct• rt ain useful ra 11gt' a nd numbers 11lilis ing the scrvic1'. rr. how1•vt•r, a reply is dc,1n·cl. a stamp should he sent. \\'ill ,,t:i11ons in art·a~ not at presc111 ,cr\'cd offer tlw11· -,e rviccs to ;\Jr. T . A. St. J ohnston (G6t;T). " :-=ormandalc," l.1ttl1· I lallingbnry, i-:_,.cx (Tclcphon,· : Bishop 's Stortlord 785). A sending s ration c;:1c II , of l'nowlc, 11car llrunton, ~. Dt•\'011, is inchukcl in tlw :<ehrdulc· hdow for the fir-.t time.

Sunday,.

i.\ lonclavs ... T ucsda-ys ... Wcclncsda\'s Thursdays-. ..

c;_.\I T . kc. S1ation 0900 I 7 SS CS:-:-F 119:!0 li92 GSA B IOOO 1080 CSPH 1 :100 1920 r.cwc 12:10 1850 G6V I) I 500 1887 G:1c; 11 23 15 li41 G IH:-\S 22 15 li92 CSPZ 23 15 I i-II G l6XS 22 15 1792 GSl'Z

Locatwn )J.anchcsl1·r Lough ton StafTordshirc )Jortldket 1.ciccstcr N. Devon Bangor Colclwstt·r Bangor Colclwstcr

/

[HJ: I . • ~ U. lll: l.l. l"l I.\". :"\m·cmber, 1938.

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PREMIER MOVING COIL METERS

Gu;araM.eed Accur:l.ty within 1 l per cent. Model No. l (u Illustrated). B•kelltc C:uc, 3 ins. by l ins square. with Ze ro Adiuster. 0·500 Microamps. O·I m.•. 0-IC> m.•. 0-SO m.•. 0-100 m.•.

) f ' · 25 , .

.. 11 6 11 16 11 6 11 6 0-150 m.• ..

0-1 m a movements wuh uflbn.ted sule volu ohms m.a. 27 6

Model N o. 11. Model N o. 311. l-tn sqv.are cue. l •·•n dumctcr

round use. 0-1 m A. 18 6 O·I m /A. 11 6 0-10 m 1A 17 6 0-10 m A. 10 • 0-SO m A. . 17 6 0-50 m A. 10 • 0-IOOm /A. 176 O·IOOm /A. 101· 0-150 m /A. 17 6 0-150 m !A. 10 • Model 3 11 . O·I m 1A. movemen<. with <>libnted sufe voft1·0hms·m /A.. 25 •·

VOLTAGE MULT IPLIER RESIST· ANCES , su•nnt .. d ucuncy .:!:_l per cent. All uandard ranees, I / l each.

TAPPED SHUNT to provide readlnzs ol 5 m /A .• 15 m /A .• 150 m /A. and 1,000 m/A .. S /6.

PREMIER SHORTWAVE KITS

are :all sold con1pleto to tho lout detail. All v:alvcs and coifs uo Included , u well as theoreti cal •nd wlrln1 dl•cnms. •nd lucid Instructions lor bulfdln1 and worklnc. Thounnd1 are clvlnc (ucullent results all over the world. Each Kit uses pfuc-ln Coll• •nd the Coils supplied tun• from fl to 170 metres. All Kits ire supplied with a steel chusis and p1nel.

r Valvo Shoft.WaYe Receiver or Adaptor Kit ... ... ... 17 /6

V.alve Shori-W.ave Superhet Con· v•rter Kit , ... 10 /·

VJfve Short-W•ve A.C. Superhet Converter Kit.. ... ... 12 6

l Valve Shon-W.av• Rec•1ver K1r 25 f .. ) Valve Shon .. W.avo Screen Grid

•nd Ptntode Kit .. 58 6

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EUROPA MAINS VALVES. 1v .• A.C. Typos, A.C. /H.L .. A.C. /l., A.C. I S.G .• A.C. /V.M.S.G., A.C. / H.P .• A.C./ V.H.P .• A.C. / P., •nd I-watt D.H. Pen· tode•. •II 4 /6 each. A.C. /Pens.. l.H .• S /6 ; A.C. /P.X.4. 6 /6 ; Oct. freq . Ch•ngers, 8 /6 : Ooubl• Diode Triodu. 7 /6 ; Tr iode Hex. Freq. Ch .• 8 /6 ; Tri. Grid Pen .• IQ /6; 3 '. ·watt D.H. Triode. 7 /6. UNIVERSAL TYPES. 20v. 18a .. S.G .• Var·mu·S.G .• Powe r, H .F .• Pen., V.i r-mu H.F. Pen .• 4 /6 each. I 3v. 2a. Gen. Purpose Triodes , S /6 : H.F. Pens. and Var·mu H. F. Pens .. Double Diode Triod~s. Ott . Freq. Changers. 7 /6 each. Full-Wave •nd Holf-Wave Rectifiers, S /9 each. 21-v. and 35v. Pen todes, 7 /6.

AMERICAN VALVES. We are solo British Distributor. for TRIAD High· grade Ameriun Valves. All typu In stock. Standard cypes. S /6 .. eh. All the new Octal base Tubes at 6 /6 ••eh . 210 and 250, 8 /6 •><h. 81 •nd lA3, 8 /- eJCh.

NEW TAYLOR TUBES T.<IO. T.Z<IO. NOW IN STOCK. Price '1..4 / - Mc.h. Prices now reduced on 866 Rectifier. now 10 - : 866 Junior. 7 /6 : T55. 45 /· : 203Z. Sl 6 : 715. 6S • : T.20 and TZ.20. 17 6 uch.

PREMIER MAINS TRANSFORMERS S<:reened prim~ries, 200..250 volu. Fully iuannteed. Wir~nd types. S.P. 250, 250..250 v. 60 m /A . 1 v. 1·1 a .• 1 v. 2.3 a .• 1 v. 3-4 ...... 11 C.T .. 10 /·. S.P. 300. 300..300 v. 60 m IA. 1 v. 1-l • . 1 v. 2·3 a •. 1 v. 3-'I a .. all C.T .. 10 /·. S.P. 351. 350-350 v. ISO m / A. 1 v. 1-2 '·· 1 v. 2·3 a .. 1v.1 a .. all C.T .• 13 /·· S. P. 351. 350-350 v. ISO m /A. 5 v. 2 a., 6-3 v. 2 a .. 6-3 v. la .. all C.T .. 13 /6. The ~bove <~n be supplied fitted w ith Panel and T@rminals. at I /6 extra. S.P. SOO. 500-500 v. ISO m /A., IS/· S .P . 501. S00-5()0 v. ISC> m / A, 1 v. l•J ••• 1 V. 2°3 a .. 4 V, 1 -3 a .• 4 V. 3-5 >.. all C .T .. 21 /-S.P. SC>2. SOO-SC>O v ISO m /A , S v, 3 >.. 4 v. 1·3 •·· 4 v, 2-3 a .. 4 v, 3.5 a .. all C.T .. 2S /· S.P. SC>3. SOO-SOC> v. 2()0 m /A., S v. 3 > .. 6.3 v. 3 a .. 7.5 v. 3 a., or 2.5 v. 5 a .• all C.T., 2S /· S P. I ,OOO. I ,OOO-I ,OOO v. lSO m /A., 21 /-. S.P. f,lSO. l,2SC>·l,2S() v. lSO m /A., 17 /6. S.P. 2,000. 2 ,000-1,0C>O v. ISO m / A., 50 /-. The ~bove can be supplied fiu cd whh Panels and Terminals. u l /- e xtra. Derails of complete ran1c avaibble. Sped.al Transformers wound to order.

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295

RADIO

PREMIER MATCHMAKER UNIVERSAL MODULATION

TRANSFORMERS Wiii march iny modulator ro any R.F. Secondary Lo•d. Triode" Tetrodes and Pentodes, Clats A, Slnsl• or Push-Pull Clais ••Alli •• and ·· 8 •• In Push-Pull or SOO ohms line inpur. can easi ly be muched to any ol the loffowln& R•dio Frequency fin.al suits requ1rlnc modufallon. Tr1odt1. Terrodu or Pentode-s operatin& under Cius ••A•• •· B:· ··BC•• •nd " C •• condtt1on1. e1lhtr S1n1lt: or Push·Pufl. Toully enclosed •n an asH w1rh encn¥Cd Panel. and lull tnurucuons. Ruin&• ue b.ued on R.f. lnpucs.

SO W att. 17 6. ISO Wnt, 19 6. 300 W att, •9 6.

A ntw nnie ol •• Matchmaker •• Untverut Outpur Translormeri wh1<h ire desicned to match any output valves to any spe1ker impedance, are now ready.

S-7 W att, 13 /6. 10.15 Watt, 17 /6 . 20-l I W a tt , 29 /6.

PREMIER 1939 AMPLIFIERS

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).watt A.C. • .• ).watt A .C. D.C . 6-w~tt A.C . 8 / 10.watt A .C. D.C . IS-watt A.C .

£l IS 0 £1 15 0 £6 15 0 £6 0 0 C7 5 0

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.\/11rn11lll\• 23SI

296

UNITS

All units a r e ready m ounted in the type U h older illustra ted, and a r e sup plied to within S kc. of your specified figure in t he 1.7, J.S a nd 7 Mc. ba nds. T he actua l frequency is given on t he Frequency Certificat e to a n accuracy of 0.025 per cent.

Type SS. The Standard X Cuc Crystal. Temp. Co-efficient 23 cycles per Mc. Max. R.F. crystal current 100 m/A.

PRICE ... Type SS unit ... ... 20 /-Type SS Crystal, unmounted IS /-

Type PS. The well-known Q.C.C. Power-cue Crystal Temp. Co-efficient 20 cycles per Mc. Max. R.F. Crystal current 140 m/A. Recommended for use in Triece and similar circuits.

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lype Q.S. An entirely new low-temperature coefficient Crystal. the drift being less than 4 cycles per Mc. per degree Cent. change. Max. R.F. crystal current ISO m /A. S.uiuble for use in adjustable ai r-gap holders.

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Telephone: Mahlm 0334.

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WODEN TRANSFORMERS n The Best that Money ca n Buy I H

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lndlvldually constructed by skllled enrlnccrs.

w 0 DEN TRANSFORMERS ARE BUILT TO LAST THEY LOOK BETTER- THEY AR E BETTER- YET

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W 0 DE N TRANSFORMERS are stocked by Messrs. W EBB'S RADIO of London and Blrmlnaham·

Manufactured by

WODEN TRANSFORMER CO. ST. JOHN'S SQUARE, WOLVERHAMPTON, Tel.: ll8l9

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ELECT RADI X BARGAINS The Dlx-Mlpanc::. Veit Pocket Tester. A compact versatile movln1-tron muhl·nnic meter lor A.C. or O.C. clrculu. No proJcctlns terminals. THREE nnau of volu : 0.75. 0-ISO, 0.300. MILLIAMP$ : O.lll mA. and ()..75 mA. In black bakellto case. ll lns. by ll ins. with pair or tut leads and olucs. Leaflet " L.H ." al•es full lnlormulon. 19 /6 Movinc Coil Panel Mlll lamm et ers. 5 mA. to SOO mA.. all sires. by Weston. Elllott. Turner, G.E.C., Butler, etc •• at baraaln prices.

Movlns Coll Micro-Ammeter. Flush panels' ll lns. Detccu batk luh arid current In valves : loatcs distortion. Reads I m /mA. per dlv., 0 to SO mlcroamps .. full scale. SO mV. movin& coil. I.OOO ohms, flush panel, ll·ln. dial, 40 I··

Mkro Relay. Mo•lnc coll u above. Fitted platinum concacu to dose at SO m /mA .. 60 /·. If you lust want a cheap back ol panel O.C. merer for 8 mA .. or a circuit tenor with pl1in scale, I-In. noedlo. mica panel and back lamp as tunln& Ind icator, Illustration shows t his, ) /9 post lroo.

T rnn1mltte ro Aerial. Radiation Meters show what you arc putt Inc out and whether It Is I amp. or SO amps. R.F. wo can supply tho Hot W ire or Thermo Mc. meter for your Job. Short Wave Seu.-Epoch $.metre battery Porublo Transteivers with Hlvac V1lv0> and Handcomb. Suitcase model In wood case. Cheap. ll Metre. Ono only. Portablo JO.watt typo with modulator. Lecher copper·tube aerial and separate A.C. power p.ack or batteries can be uHd. £9 16•. Od. Come to us for Dynamos, Rotari e1 and Switchboards.

ELECTRADIX RADIOS 218, UPPER T HAMES STREET, LO N D ON, E.C.4 ~~~~~~TJ<Pltotv: Ccnlro/'4611 ~!!!!!!~!!!!!!!!!!!!!~

just Published

A SIMPLE GUIDE TO TELEVISION

By SYDNEY A . MOSELEY & H . J. BARTON-CHAPPLE I Wh.Sch., B.Sc.(Hons.), A.C.G.I., D.I.C.,

otc.

You should get t his book at once. It is intensely Interesting and enlightening. It tells the simple facts about Television and answers the questions t hat ordinary people are asking. It explains in understandable, non-technical language how Television originated and how it works, and concludes by describing some of the developments which may be expected in the future. 43 pages. I /· net (by post I /3).

Order from a bookseller or direct from

sm ISAAC PITMAN & SONS, LTD. Parker St., Kingsway, London, W .C .2

TH E T. <!>- R. BUl.LE.TJ.Y, Xovember 1938.

NEW MEMBERS " '""· CORl'OKATI.

"· AffnOTT (C:lj \' ), 70, )l.lNlrll Hoad, S.S. Bl.ttkpool. '·'"'-"· F. J ~~~~" (G:J:O.:j), l hr C<111agr. Crookhill llall. Co111,l•m>11gh,

\. C11Ar1.1s (G3:0.: fi). i5, fini~ht<clilfc Avrnur, Gl.1'~°''. \\'.3. r. K. DARLOW (CSQX). " "1...:'> ll:llt." Da\\-.;tone Roac1, H..-wall.

\\1rnJ. c~. I. II. PARKIS (C30l'I, ~I. (~rr~,: llOIL.., Cr......,nt, Sfl<-tnrkl. ;:., I. G11r:asos (G\13.'>A), .\lt,•tt Fnrtt-. \lnra,,hJn>. Srotland. I'. • .\,DEll'O' (G:JTQl. "\\·..,.1 \'1•\\,'' C.&J«lonia11 l("ul, We>t

llartlcpool, Co. 1Jurha111. 1- G. PAtRl<AS (G)l3l'.\), \1l<a \'""· llarv '>tr.-.·t, llunoon.

Srot1.1nc1. t;. ArPL!:.GATt~, Junr. (:.!A~N), 70, Frome Rnad, rro,\bnd;.:t?,

\\.Ills. I'. J. G11c s Dv (~OG I ), :I, Unr.·11rr Street, l'olkestonc, 1'cui. t ~ . P. )llLLAR (20C \\'), 8, lter111itu.f{e Gard<"ns, f!•linhun:h, t(J,

Scotland . \ , .J . )hTCll CLL (:!Dl,X), 2r., Gnrden Cl<"". Addlrstonr. Surrr,·. E. " E•Tts (201'H). M, St. \lnry S t reet. \\'"·mouth. Dor><>t . · \\', Hu>1 P11 R1as (~l)QV), tlll. C:u.·el1 l.inc. Smalflleath. llm11in~ba111. H. 0 . H OL'IA ' (21)\')(!• A•hhtld, Kio~briclge. South l.>t,on. I'. A. HA1tR1~ (~FCC), :.:i. fifn~~brlcli:c Road. l'ar~>tono, Oor>et . \ I. A. CRot·cu (21'1 !(;), \\'attnng I h it, )lanea, Camli-. \\'v. lltLL (~F I' fi ), 3:!, \\'ll"lorcl Street. Stapleton Road. llri-tol. 5. 1; , G. EA<Twrc.:·l'tuu (ll l<S:ll 2!1) (now :!F:O.:\I), !'nor '< ll a tch.

Godahn ing , Surrev. I>. W. EvAss (IJRS:ll:!-1), 87, Mhford ;\\'enuo. llayrs, )lu lclbex. W. F. '1'110>1sos (llHS3 1~6), :!!!, llullon Grow, ' North 1'111chkv.

London, N.12. A .. \I. H. MALLOCI< (llHS3•1 ~0), J(o \':il Si~nals ~loss, C:ortcrick Cn01p,

Yorks. · c: . W. PARKS ( llJ<S3 1~7), "Troon," Burrill A\'cnu•. Cosham .

Ha nli. 1\. C. Ki se (DHS342S), II, l..ukcsidc Drive, Bromle\', Kent. I'. E. G1·u.v (flRSi14~>0), II, O>bome A,·cnur, AsbJc,· l:io\\11. Dristol. E. B LCKWITll (DRS.11:111). r .. Try Road. C<><:_<:e<hall. E-;,-x. J .• .\. EASTTRHROOI; (111<!>3131), .. )lariield," Cacle\\ell L:111r.

Torqmw. De\'on K. josi:s (BKS3~3:!). 111<, :O.:orth Road, Clowne, uear Ch<>tcriiekl. G. SAIS•Bt:RV (8RS:ll:J:I). l..otkmg·1'ro><lc. Tn1'•!Jrid~e. \\'ills. :-:. H . )IU~WUL (OKS3 13 1), 7, Pal~r.&\'C Road.Great Y .. nnouth. s. \l~ADOWCROl'T (DRS:S I&.). ~'II. Shakcs~are Drlw. Chcadk.

Cheshire . • \ . &. l'ovsnR ( 111(53436), 11', H;1111cs J\\·enue, Carlton Road,

Worksop, Nou s. 1\ . I'. CRltTTOS (llHS:1137), 3 IO, <.«11mor Road , Port>mouth, 11,tnl>. T. XooLHT (DRS3 t :l-~). :! I , \\'ooc1fands A\•enue, l're<ton, Lanes. F. G. Snt:PPARD (Olls:J4:l0), 140, ll'avtrle" A,·enur, T";rkenham.

Middlesex. • D. D&V££.>' (DHS3~40). 2 1, l'o\\U S<tuart. London, \\'. 11 . J. S. SsowBAl.L (OR.."31 11), l<t A.A. Ude. Signal<, lll•r kcln""· nr'1r

.\klershot, ll•nti.. S llcfiA v (8RS3412), i. •• \•hi:n"'t' Road \\'r<t .. \~rdctn. I'. R. )IAV (BRS3 H 3), lhl~r-..t, llirwin'1ham Kood, \\'~ttr Orton.

r.ea:r Birmingbnm, \\'ore. . .\ • .\TTWAU R (DRS3111), " \\'ooc.113.nds." Follaton, Totn«, Ocvcin. 1;, "- llALEv (ll llS.1 1 tro), " Ingleton," 3 1, Bemadeu e A,·cnue,

Anlab>• High Ro.ul, 111111 . II. A. WH EATLBV (Ul<S:I Ill\), 4, C.rnn Hill, Taunton , Somt rsct. S , G. RAYN ER (BRS:l-147) . 2 11, South Pa rk Dr ive, llfo ril, l.'S:<e.• . I'. n. C!IAPPl;LL (0](53 141\), ~··· E hn Road , Beckenhom, Kent. J;, D•v1es (BRS3H !I), 8, Clrn thom S t reet, Hothcrh:un . York~. F. HILL (DRS3150), " l>ln~ lcy," Oxford Road , T 1lehurst·t>n·

Thames, Btrks. R. JACM~Os (0HS.1 1(J I), ~. )lillord Grtwe, Stockpnrt. Lhl'<hirc. .f. S. S<:OTT (0HS34621, Il l, Gallow~Jtr. Aberdeen, !Xotlancl. IC D. WARR8S (Dl<Sa453), St. John's Home, AIHrtnn. l'•·mam c,

Com wall. \\'11. S. ) I URRA\' (llllS316 l ). '' Hoc.kfort," Tannock Om·e. ) litn ·

ga\oie, C l3SFOW.

I'. )~;·1~~d~ ( llHS3 I r.ri) , (10, lloydhcld Avenue, l'r<•twick, Ayr.

I'. )1. BRADLr.v (lll!S:l4r.H), C1oxto n l\crrin l, nc.ir Cr>ntham, Lines.

I', DAvrn (flRS34G7), "l'nlkcners'." 1..ipbook, Jl anl<. 1)0)111\ IOS AS U F OJH!ICN

c:. I<. )IOUSCR (VEii\\'), :''r" llOrl I.and, Hant> Co.,:-.;,.,., &oll.t. Canada.

\ \'. A. lloci; (\ 'fi ll'CI. l'•111l<>ra Cre«cnt, Pon ~lort"<ll\', l'•pua. r. \\'. J. HOJ<t;WOOJ> (IU:l<s1:;:1). l{melb w, r """"'"· \l•lta. J. H "" (Hl!R~S I ), II \l.S. I ~"'· t 'o G.P.0., Loudon.

The Utility Two- Valve Transmitter It is regretted t hat C l3, mentioned in the caption

under Fig. 3 (page 71 . August issue) was omittt'd from the circui t di:tgra m. Jt should be fit ted close to the neutmlising condC'nscr \ 4, a nd on t ill' g rid ' idc of the latter.

297

F.O.C. NOTES By ll. \\'i;nsrnn (G5J3\\')

H is with considerable regret that wt• ha,·c lo a nnounce the resignation of two o f our Committee membcn;. ::\lr. W. G. Gillan (EIS::\l). who was s ta tioned a t Spike Isla nd and lall'r at Bereha,·en. has had to clo•e down O\\ing to t hl· wi thdrawa l of the English garn"<>ns from Eire. I le is now stationed at Bulford Camp, but hope-; to be act i,·e again as :.oon as circumsta nces permit, possiblr wit h a G call . :\lr. E. F. Baker (GSOQ) has decided to de,•ote his future activities almost exclush·ely to 56 ::\le .. and consequently has had lo gh·e up Commiltct• work. We t ender to them both our sincere thanks for their invaluable work. especially during the t•a rly days or the Cluh. and note "ilh pleasure tha t they s till " ish to re tain thei r Club membership.

Tn consequcnCl' of these resignat ions the work o r the Ex1·cuth·e has been ra ther disorganised. but despite this we ha ve accomplished a fair amount. and hav<' .. nrollc<I six new members during the month . \Ve a rc fortuna le in lwing a ble lo fill the Committee vacancies with i\fr. A. C. I?. Dearlove (G2QO) an<l i\lr. j . i\L Davie (G2XG). both of whom have had extensive amateur and commercial experience in ,·arious pa rts of the world.

The f'.0 .C. propo:.c<l As!>OcialC' "chemc has now been d iscu!IBed and appron !d by the Executive, a nd the majority of members an• in favour. The "outside " rc,,poni.e. howe,·er. has been disappointing a nd only a few letters on the subject ha,·c been received. We sha ll sec what e \'entuates during t he nexl month, a t t he end of which period the scheme will he droppc<i if the support is considered inadequat e. Perhaps we should explain here tha t the proposed scheme docs not iO\·olve the indiscriminate admission or each a nd every applicant t o the Club. Prospecti,·e A~cial<•s would ha ve ro pro,·e a minimum morse speed o r 15 w.p.m., and also show definite promise not merely by their general tech nique but by thei r willingness to accept and act upon the advice of those q ualified to gi,·e it. If the scheme is not wanted we have no \\ish to prC'ss it , and a rc content to leave the ducision to members themselves.

The production of Club crrtili c;~tcs is now well nnder way. 0 1 t he several t•xccllent designs submitted, that or '::\Tr. B. W . W. Oliver (2DR::\l) was fina ll\' chos<'n, a nd the block h a.~ just been received fro m 'the engraver~. P rinting will begin as soon as certa in a ltcrnatl\'C propositions h:we been investiga ted . We hope to have the ccrti f1cales ready fo r dis tribution in the near future.

::\[1•mbcr,; clc•ctcd during the month arc: G5RX, GSl'l, CGDI._, GGLF, Zll l H and GW2 NG. The total rn \·mhcrship is now 47.

Pkasc atlclrt·~s correspondence to Radio G5BvV, \\'illingdon , Eas( bourne.

Strays ::\lr. G. ~ykc ... G2JC, infonns us that he ,~·orks

exclusi\'cly on 14 ::\le. therefore contacts 'nth a station using his call on 3 5 and 7 ::\le. must be regardL'Ci as being "ith a pirate.

* * 1t :\Ir. Patrick Lcba11. F3H K. \ '1 llcneuvc. par Brion, )Carne·el -T.oi rc, France, would like to correspond with a Hri l i'>h amateur who i~ interest ed in syncopated muc;ic.

298

A.R.P. AND THE AMATEUR The Edito1, T. & H. B\:Ltl'.TI~.

l>l!AR Srn,- M;n· I intnidc :i fe w comrnt·n ts on recent correspondenct· in t h1• Hvl.l. l(TI~ on the :ihovc subject ?

I a m sure that m·arly all of us will uphold the l'Xpressions of opinion gh'en in the last two paragraph,, of :\!r. Jack:.on's letter, and look forward to the time "hen r<'a»0n, consideration for oi her::. and a. spirit of international co-operation, will ;e:.uh m the rcmO\'a l of many of thl' degrading influences '?f present-day m~tiona l li fe among them a1r-rauls and th,· associated prccn11tionar,nu·asures they involve. •

Meanwhile, unti l t hal happy era arrives. le t us ha\'C realism, for only by fac ing up to t ht• conditions as tlwy exist to-clay can we hope fo r thdr eventual improvement.

:\!any who ha\'c had long CXJX'ricncc of 1nt.-r.:ommunication arrangement" arc con,•uu·cd that t he only sound principle under abnormal condition:. (and conditions during air-raids would hl· ''«ry much so) 1s to make use of all known met hods. individually. o r in combination. according to ci rcumstances and local requirement s, To withhold on(• method on ethical g rounds would be absurd.

If t his is ad mith•cl it is t'Vident l h;Lt pressure lowarrl~ t he inclus ion or t he amall'ur network wi thin t he national com munirntion srstcm is best 111iliated and sustainl·d hy a rcprc,,cntntivc bod\' M1ch as the R.S.G.13.; indi\'idual eflorh lo this end ~annot hope to rccch·e the same cori-idcration in high places, nor put fon\'ard "11ch complete and comprehensive propo~a l~.

l\kmbers holding :'ll r. Jackson's vil•ws, a~ expre,,~ed in the l·arlicr portions or his lcttl·r. as a reMtlt o_f which lhey \\Oulcl. presumahl)". agree to u:.t• their apparat\1" to ~ummon a fire-<·nginc to a neighbour's house if on fire owing to carelessness, hut not to obtain an ambulance for the succour of human beings injured 111 an air-r;11d, \\Ould ha\'e to examine their con:.c1ences as to the extrn t to which t hey could agrec to participat e in a ll\' na t iona l scheme. which must . in a ny case, he orga nist•d on a voluntary hasis.

The recent crisi~ has hrought into the light of day much of the par tia l A.R .P. o rganisat ion which has heen so s lowly a nd lahoriou~ly built up during t he la~t three years . . It \\OUld perhaps be not unfair to say that the p1cturt' as a \\hole is not one which ha-. produced a feeling of ,ecurity nor a corwiction that . arrangement;. arc sullic1ently complete. It '" C\'1dent therefore t hat a great deal of pressure is ,rc_quired from many quarters to ensure complete dhc1cncy: and I urgf.: that our Society should no i. relax t heirs on the subject under d iscussion.

• 1\11 incomple te A.H . l '. »Cherne is <1 11 opc11 invita~1c111 to attack ; the conver:.e g ives every lw pc tha l 1l rnay nc,·er ha \'e to be brought int.o usc.-Yours fa ithfullr.

II. LEE-\\'RfCllT (J3RS34 I 7).

Tfff: 7. ~ U. BLLLE1 /,\', ::>:ovember 193:'

The Editor. T. & IC Btll.Lli.TI~. D1iA1< Sm,- The lasl issut· o f thl· f31·1.1.hTI~

co11tai11l'<I an inw rcsting editoria l com ment n•g;mling the possible use o r the ultra high frcquc nei1·-. for local <"o mm unications in connection with .\ ir Raicl l'rl'cautions. A few days ago a national daih· lll·wspapcr staled :-

.. OITt•rs to assist in ,-\ . H. I'. communicat11111"' \\Ork ll\' amateur wireles~ c11 t husiasts who operate o,hort-,\.avt• transm itting :111d receiving >Cls ar,• bdng- rt·c1•ivcd in la rg1· numl><.• rs hy ~ortla·rn A. IU'. a nthorit ics.

" So far the a uthoriti('..; haw not decided to utilis1• short-wave rndio operated by amateur,, but the po:.sibili ty i!< being considered." For -.ome time British amateur transmitter:. ha,.,.

been eligible for sen·ice in the Hoyal :\a,·al \\'1reJc.,~ .\ uxiliar\' Resen ·e and the new wirele~s re~cn·l' of the lioyal Ai r Force will prohahh· attract <1uite a large e11 l ry. ~evertheless. there mu,,t be a larg,· number of a mateurs in tlw countn· who a rc nnt sncmlw rs of lhc reserv(' organi~ations a nd who would li ln· to assis t llw civil a.uthnritics in /\ . R . I'. work.

The n·sponsibility for th,· i\ . lC P. schemes h.1, bee placed to a g reat cxknt on t he 1.ocal .11111 C:ounl\' authorities. These :\uthorities han• h<.'<'ll advi:.c'd ll\ the Home Office that the tch:phosll' scn·1cl'. .. upplemented by mr<sengers. mu .. t Ill.' regankd as the nonnal mean-. of communication for A.H I' ;1nd it is stated that whibt telcphom· cablr~ may be damaged by bomhs l>erious dbloc;1-tion of t he Sl'rvice on this account is not anticipated.

Nal11ra lly the Post O Oicc has ma ny altcrn;sllw caliles a vai l;1hle so tha t the breaking o f a few li ne~ would probably not scriou:.ly a tfrct the system a~ a whole. but it seems reasonable to a-.:.umc that hy rcao;on of thci r st ratcgit• importanCl' the m;un telt·phorw t•xchangcs will he the very buslcling~ which an encm~· bomber will attempt to de-.troy. '.\lorco\'er it would appear that damage to ii tl·J, .• phone t•xchange made up of IOCO'll, toll. and trunk switchboards will paraly:.c telephone traflic owr ;1 wide an•;1. In this regard il b in tcrc,,ting to r<·call that during the last war till' Ct•nlral Tell')(raph Onicc in London was bombed in an ai r raid .

la times of emcrgcnc~· till' :\nll'rican amatt'ur, ha\'e re1wah-dly demonstrated tl!l'ir abihty to masntam radio communication Jong .1fter tciegraplh, tt•lt•phonc.,, and e\'en the hmadt·a .. tmg ;,tall<Hh ha\'C ht"t.·n put out of action. In this country wt· do nol have to face floods ;rnd s torms anything like those cx1w ricnccd in the l i.S.A. h11 t it is not i111 -probrd1lo l hat we may hav~· to face an cnH•rgcncy fa r grcah· r t ha n any natural agency could ca11St'.

Radto could be so u~cful in A. l{.l'. ~clwme-. that 1t i-. difficult to understand win· the c,1\'l'rn· mcnl ha., not launched an :\.H. I'. Iiad10 network. It 111;\\' lw argued again:.t the idea that by listening to thc ... talions concerned an cnenl\' could obtam information useful when compiling ·reports on the result of 1·ach raid, but the use of C.\\'. and a frequently changed cipher would obviate thh danger.

In laf!~l'r citic~ il might he useful lo a rrang(' for one of lhe bette r equipped local a ma teur stations to opera t e on the broadcast ba nd should it be necessary to broadca~ t messages to the civilia n popula t ion ; the 13.13.C. stations would probably broadcast information of a na t ional rath~r than local nature.

THI: T. <5- R. BULLETJS, =--o,·cmber 1938.

:\!any months ha,·e passed »inCl' lhc possibility of utilising short-wave radio for A.H.1'. was mentioned. According to the trade magazines, in one or two towns radio communication has been used in A.R.P. exercises (whether authorifr for the cxpcrimenL-; was obtained is not clea-r). but if amateur radio is to be brought into lhc A.RP. ~cheme it will require some organising work which must of necessity take some lime. Rather than olTer their services to the local authorities which can do no more than Home ()Hice instructions allow . . wo.uld not it be best_for the amateurs willing to ass1st. 111 A.R.P. to get 111 touch with the Home Office Air Raid Precautions Department ? What''''er the an~wer of the Home Office ma,· be, the authorities will at least be able to form !>Orne idea of the number of amateur stations available.

Yours faithfully, A LA~CASllllll! .MEMBER.

MODIFIED W 8JK BEAM The Editor, T. & R BuL1,11t1:-.

DEAR SIR,-1 was Yerv interc~tcd to read )lr. j. ~. Walker's article in -the September BULLETJX conceroing his modification to the WSJK bean: aerial ; but l would appreciato an explanation of the following points. Firstly, l fail to sec how the true "out of phase" operation of the SJK is arrived al by his method. since. while feeding at a current point the two elements to one side of the aerial would appear to be 111 plmu. Secondly. it would seem that the arram:cmcnl could be resoh·ed 111to a simple dipole-at least on the lower frcquencic:i.

If you could spare me a little more of your valuable spa.cc- in order t hat my criticism may not bo wholly destructive, I should liko to suggest a method which in actua l opcmtion at my statiou has given very effective results.

The trouble, when using a matching stub, is t.o match a low impedance feeder 11110 it. As )fr. Walker has pointed out, the impedance at the bottom of a stub is far removed from SO ohms, so that an impedance mis-match will result should the feeder be connected at that point. In order to overcome this difficulty, and to do away with the use of a stub. which is a nuisance 10 erect , and has :m uncanny ha.bit of getting hitched up in other things, a coil was substituted.

This coil was made to act a~ a resonant haliwave on U1e band for which the aerial was to be used, and ea.re h\ken to ma.kc it self-resonant, since the use of a tuning condenser in parallel, though easier, has distinct disadvantages. Under these conditions, lhc two opposite onds of the coil will !Jc at high and opposite voltage. This is exactly the co11dilio11 rcq11ircd at the top of a stub. A correct impedance match to this " tran~former" from the line may be had by putting a one or two tum link round the centre. and connecting the two ends of the coil to the feeding points in the aerial. The adjustment of the coil is critical. and to bring the resonance peak to the required frequency (in the writer's case to 14,300 kc. approx.). lhc turns must be adjusted to the nearest half turn. The arrangement has been fottnd to be as aperiodic as a stub.

For those who would like to try <>ut. the above scheme, some details may be of use. The coil consists of 17 l turns approximately of No. 14 gauge sing lo enamelled copper, close wound. on a former of exactly 2 ins. O.D. A lwo·lurn link round

299

the centre wa~ used, and, afrcr adjustment, tho whole was dipped in molten paraffin wax. The aerial is a two-section \VSJK for u~c on 1-1 :\le. The final resonating of the coil 1s best carried out by two people- one at the transmitter while U1e other adjusts the turns for maximum current at the centre of any of the four half waves. The Yery able ass1stanco of G8HA made the clotem1ination or the coil siw considerably easier than it might have been.

Such a method need not be confined to the;- WSJ K, but has been used in similar fom1 for phasing up other voltage-fed arrays. The increase in power m tl1e aerial with the phasing coil, over the stub, 1s most marked, and has the added ad,·antage that 1t is \'Cry hght. and the SO ohm feeder can be taken right up to the aerial.

Yours faithittlly, R. W .. \uom (CSL T).

IN REPLY Tltc J::dilor, T. & R. Bu1.1.1tTIN.

DF.AR Sm,- 1 thank :\lr. R. \\' , Addie for his criticism of tho aerial system shown on page 143 of the September But.t.&TTN, and, after consideration of the point he raises. I agree that thoelements of the aerial shown in Fig. 3 arc actually in phase. The operation is, therefore, different to the original Kraus aerial. but the results arc. nc,·erthcless, "ery similar.

It has been pro\'ed by practic:1l tests that the radiation b a. ma.x.imum broadside, a.nd. Iurther, that the beam b one of narrow angle. It would appear that the ;ierial is really of the 13arrage or H type, and it is probable that lhc results would be better if the aerial was erected in a vertical plane.

On further consideration, there i1ppcars to be no reason why low impedance feeders should not be conncclccl direc tly in place of t he stub shown in Fig. 1 when. under certain conclit ions, the correct out-of-phase excitation would be obt:tincd. These conditions can best be explained if we label the arms of the aerial in Fig. I as follows : top clement A and B ; lower clement C and D ; centre point E. If now tho length AEB is made a resonant half wavelength. low impedance feeders will match-in properly at E. Again, they will match-in al the second hair wa,·clcngth formed by CED. but due to the cross-over, the latter will be excited in opposite phase lo the top element.

lt should be pointed out that the S\-stem as shown in Fig. I is a ,·oltage-fcd one, and· elements AEB and CEO must be full wa\'e for the band in use. Mr. Addic's syslem of using a coi l in place of the stub is lo be recommended, but il must again be noted lhnt it applies to a vollagc-fcd aerial. If two single half-wave elements arc used, lhis means thal end feeding is necessary-the coil can only be connected in at the centre if the aerial a.s a whole is full wa,·e. As :'llr. Addie finds it necessary to adjust the coil ,·ery carefully to the resonant frequency, it can hardly be said to be aperiodic.

Yours truly, ]. ~. WALKER (C5JU).

OLYMP IA GEAR The Jl.ditor, T. & R. BULt.1n1N.

DEAR Srn,-As one of the meml>crs who loaned apparatus for display on the Society's stand at Radiolympia. l should like to reply to the remarks of .\lr. C. C. Oxley, GS:\£\\', which appeared in the October issue or lhc Btrt.l.ETIX.

300

His question as lo whether any of the transmitters could gtl dow11 to 10 waus is, l feel, worded rather strongly, and 1 !>hould hke to point out that in my apparatus the input to the anode of the \-ah-e deli\'eriag power to the .1.eri;LI circuit has not yet exceeded 10 watts. The transmitter in quc:.tion was used al District 13 :K.F.D. on the 1.7 .\le. band under the super"ision of the D.R. and has also been used by G6IO when portable at \\'esterham Hill, Kent . \\"hen u-.cd al G610, a 60L battery (nomtally u-.cd for fixed baa:.) was in u;;c as the H.T. supply. The input at this time \\"aS 480 milliwatts, and an "HA" was raised on 14 ;\le. C.\\-. and lhc report rccei\'ed was 579x. 1 think that settles lhc point of efficiency ! Conditions on the band at the time were exlrcmdy bad, only three or four stations being audible.

I am not acquainted with the " well-known amateur " who uses a ,·ah·e of 1.7 .\Ic. with a 50-watt filament, but I should like to point out that when my trnnsmitter was bt:ing used with a n anode input of .48 watt, t he Jila.mcnl wattage was still 5.5. walls.

With rcforence to the thirtl paragraph of Mr. Oxley's letter. I would suggc~ t that the 11111jority of British licensees ha\'e not the fat bank balance wl1ich is mentioned, and al;,o that the majority use C.W . telegraphy as well as telephony. Anyone who can read code will know that the <pccd of sending on lhe various :111mteur bands, including 7 Mc .. is invariably higher t ha n 12 words per minute, and I feel that the statemc11t "scraping through the telegraphy test " b a \'Cry uncalled for exaggeration.

With reference to the remarks regarcting " Fancy QSL cards." I "hould lake to s:Ly that I ha,·e yet to sec a G QSL which really de-.crves that title.

1 am in full agreement with G2Jl\:'s 192 1 statement llml " wireless cxperimc11tcrs " should design and build their own apparatus. though it i~. of course, quite essential to purcha:-c certain components.

The mcmber,,hip may like to know that the halfdozen amateurs in my chstricl (not District 13, but Charlton) nil construct their own apparatus, inclnding rccci, •ers.

\ ·ours faithful h-. GrnH(;" G. CHtFf't;\· ~ 2Dl{Z).

CO-OPERATION REQUIR ED Tltr 1:t1ilM, T. & R. BuLLETrx.

DE1\R St1\,- Hcccntob,,crvati<>ns taken in America have shown thitl 56 Mc. ]))\ during t he snmmer months i ~ associated with a bnormal ionisation of the E lay••r of the io11osphcre. The <[Uestion naturally arises, " T~ the lack of long-distance contacts on 56 )le. in Europe 1lue lo lower valne" of ionisation i11 the E !aver or to lack of acti\'ity at suitable 1listanccs ? ;. ·

In order to find an a n"wcr lo this. all(! <dso to obtain some itlea of lh(; occurrence and dis tribution of abnermal E ionbation i11 Europe it is pr<>ro»ed to undcrtak(; an in,·esti!(al1nn 'imilar to that carried out b,· Pierce an the l·.s A . but on 2S and 14 .\le. Shon· skip conditions on tJw,,c bands ha,·c been gh·en careful !>tuclr at thi' l.1bomtory durmg the past summer, but very moany more observations are urgently needed. i\lay I appeal lo those members who made short skip contacts on 10 or 20 metres between the bci.;inning of April and the encl of September to ~•·nd ml.' details ? Reports

THE T. 6- R. BULLETI X, ~ovcmber 1938.

should gi,·e the date, the exact lime of the QSO, and the signal strength reports exchanged. Correct identification of the stations concerned is of course essential. Reports from BRS members would also be very welcome, particularly if not only the station heard is ntl'ntioncd, but also the call-sign of the sta t ion with which it was in contact.

As an indication : short skip on 14 i\lc. would cover the Hriti~h 1-.lcs, France. Uelgium, Holland. Denmark and 5outhcm Xorn':ly, and on 2S .\le. the whole of Europe.

I hope that as many membcn; as possible "ill co-operate by looki ng through their logs and sending along the necessary information. All reports will be acknowledgccl.-Yours faithfu lly,

L. G. STOOOl. IW (G8D)1). The Physical L1.bor:1tory,

University Colk'ge. Southampton.

PUBLIC SCHOOLS EXP LOR ING SOC IETY

The Editor, T. & R. BULLETIN.

DtcAR SIR,-J~efcrring lo our last expedition to Newfoundland, I think you will be interested to hear Utat :'.\lr. Stansfield (V04 Y), of Corner Brook, one of your members, rendered us \'cry Yaluablc assistance.

H e listened in for us every night during the whole expedition, and in that way served as a valuable link between the expedition a11d various people in Xewfoundland.

This is the second time that )lr. Stansfield has helped us in this war. and I want to record our appreciation of all the trouble which he took for us.-Yours very truly,

G. i\IURHAY LEVICK, C/1airmn11 a111l 1/011. Lender.

A FINE RECORD AND A COMPLIM ENT

The Editor, T. & R BULLl~Ttx. DEAR Srn,-ll av111g just contacted my I,OOOLh

G station, Lhis calls ror comment that I believe will be of general in terest lo Hritish operators. While appearing at fir~t glance as a mere operating stunt lhe real reason here has been the enjoyment I ha,•c obtained i11 working such good operator:.. In my opinion, taken a:. a whole the G's a rc" tops," their radio ma1111crs arc Vt!ry nearly perfect a nd they <trc models for correct proccd11rc a nd operating p ractices. I have yet to identi fy as coming from them a ny 0 £ th is unnecessary tes ting which is unfortunately so prevalent on th is side of the water. They excel in " rag chewing" and Lheir QSL record exceeds a ll other nations. Kow you can understand why 1 go after G contacts in p reference.

Jncidentally, :t few figures on these 1,000 G's may be of interest. They were contacted in 1,939 QSOs with G's beginning with G513Y on February 16, 1928, and ending with G3FS on October 6, 1938. SeYenty-three were in Scotland, 3 1 in \\.a.10$, 22 an .:\orthern Ireland, three in Channel Islands, one in the Isle of )lan and the remaining 870 in England p roper. In the 54 :.hires of England and \\·ales, including Isle of .\Ian and Channel Islands, stations ha,·e been contacted in all but five : Brecknock, Cardigan, Hereford, Rutland, and Westmorland. Alt hough I ha\·e a record of over 200 additional

TJ-lh ·1. cS- }{. BULLET/.\", :\on~mber 1938.

station~ callcd but not contact ed I have ne,·er heard one from these ,,hires. Onh- l.J of the 38 Scottish :.hin:" ha,·e been cont;1ctcd but there I feel sure many districts ba,·e no operators. First \V contact,, were made with GI of the~e and two, G3lJS and G3j X. actually marlc their first QSO with me.

Again let me cxprc":; my appreciation and thanks 10 all thc~e operators for the many enjoyable contach and now that l have attained this numerical goal l hope to see them all more often and for even more enjoyable chats. 73.

)lll .. ES \\'. \\"hlcKS (\\' I \\T) . 9 1 )l:lrion Street.

Brookline, :\las!>., r .s.A.

DISTRICT 10 The Editor, T. & K lJULl. ET I N.

DEi\R Srn.- 1 feel I cannot !c l certain remarks in las t month's District 10 Noles pass without some romrnon l. J refer lo tho pa ragraph complaining of lack of" Ham spirit · · among Swansea members.

1 resided in Swansea until recently, for a considerable time, and in my opinion the·" Ham spirit" exists as strongly there as anywhere else.

I know most of the Swansea group very well mdecd, and l rccch·cd any amount of help from them- in fact whene,·cr 1 requc~ted it. They were all most willing to place their knowledge and experience at my disposal, for which I thank them.

I was only an observer at the 3.5 )le. XF.D. Station m that district, but I can well imagine that a lively post-monem has been held. I wish I conld have attended the meeting.-Yours truly,

CARL tlRO\\'N (G3QL).

AN OLD TIM ER LAMENTS Tlie Editor, T. & R. IlULLETI:>.

DEAR S1R,- \Vhcn an "Old Timer" reflects on lhe mania of µrescnt·d<ty amateur:, to outslllne each other with the collection of QSL cards. certificates, etc., shed a tear for the passing of real experimental work in our hobln·.

Time was when" ~\II signs meant that the holder was one from whom scrions co-operation might be anticipakd in radio experiments, but alas, the trend of our movement seems to be towards rubber s tamp QSO's, the use of childlike phraseology, a nd the indiscrimin<Lte use of signals meant for C. W. inappropriately applied to telephony purposes.

Consider the degradntion that a "Test Call Fiend " must experience to learn that someone has worked a new country, and the hours that a rc spent cluttering up our bands with chatter which has no reference to the science of raclio, but invariably deab wiU1 l>O and so and his latest blonde, o r bas loud reference to DX, with abundant sclf-glorificat1on.

The writer feels that the time has come for the RS.G B. m conjunction with the licensing author-1t1cs, to take measures to clean up our bands and thereby ensure that both old-timers and newcomers arc able to carry out 1111dersla11dable commnmcation in morse. If you doubt the necessity for such action, try lis t ening to the utter rubbish thnt masquerades for International Morse. L \\'e hnve listened 1-Eo.)

" Dr:iss Pounders •· arc not the only offenders, however ; listen 11.ny Snn<lay morning lo the absolute

301

dnn:l winch 1Ms,cs ,1., the con,·cr..auon of rational and S."lnt' J>l'Oplc, and explain the need for sa}ing "Hi, Iii," " \\"lw<.'1 1t away," etc.

Surely it is still pos..,iblc to obtain pleasure from our hohhy without recourse to such senseless proceclurt·. \\'ith <k-l·pcst lamentations.

\"ours \·ery sinccrelv, L. \\'. 1 lom;i-:. (G5XH).

A "Harn" Holiday in Holland Hy H. II. :\h"ERS (GGHF).

The rcce11t parai.:raphs in the B1:LLET1:> concerni11g the I lohclay Exchange Scheme sponsored by D.A.S.D., with the collaboration of X.V.LR. and E.D.R, promph•d the writer to record his expt•ricncc., in I lc>lland last summer in the hope that othrrs will takl' aclvantagl' of the facilities offered to exchang1· vbit s with overseas amateurs.

The holiday to he described was fixed up with the dir1;ct cc>-01wralio11 of PAOJ A. but if members arn unahll• to make arrangements for themselves in th is way a rartl Lo JtS.G.B. IH:adq11artcrs will ensure that Lh('y arc put into touch with the appropriate official i11 the country they wi~h to visit.

l'AOJ A (:\lr. \':tn dcr \\"ccle) and his wife came to Engla11d for a holiday at Whitsun, and by ill\;tation of the wrill.'r spt•nt tht· time ";th him at hb home in Bingll·y, \"ork.,. .\!though their srny wa~ short, ,;,its were made to a number of local amateurs, including C'.?sl·. (;().)((' and GGC)S. Trips to the hbtonc parh of lht· county and it-. capital also added to tht• enjoyment.

In July th\· wnl('r and hb " ·ife began a re turn trip to 11011:111<1, ancl, after cros~ing from Hull, where GHUI. \\a-; waiting to meet them, they were gn:ctc<I hy l'AOJA, who had tra,·cllcd from \ ·elscn to Houcrdam.

D11ring a most ph•a-ant stay al Vlcscn a number of \'i~its \\'('rt' made 10 neighbouring amateur stations, and 111 ('\'(•n· case a warm ancl enthusiastic reception \\'a-. accortlt'd . PAO:'\P, who had just returned from a mobile 3.5 :\le. Field J)a\·, showed off hi:. v1•rv hm· receiver and sc,·eral G"., '~ere tuned in. Arrangcnw11t::. were then made for a visit to the :\. \·.1to. hroadca~l111g :;tudios at J-lilvcr~um, a trip

(C1mli111w1l 011 page 3 16)

C6H F on t he ri1rh t with the 011erntor• of PAONP

30'.? THE T . & R. 8(J/.l. ET IS, :'\o\'ember 1938.

NOTES BRITISH and

NEWS ISLES DISTRICT REPRESENTATIVES.

DISTR ICT I (North· Wtstern). cC.:umberland , \\"es unorlan<l. Cbesb.ire. Laocaslurc.J

•lr. J. Nooa w (GGTW), Fem Villa. Coppice Road, Willanon, n .. r Nantwich, Cheshire.

DISTRICT 2 INorth-Eastern1. York• hirc (Wctl Rtding, and part of l'iorth RidinaJ.

Mr. L. W. PA OV !COl' YJ. l~. Huddersfield Road. Barn1ley, Vo•k•

DISTRICT 3 ("'est Midlands). (\\'al'\\ lck , \\'orccstcr . Staffo rdshire, Shropshire.)

Ur. V. M. Dcs11 o~u (Go\'M), 199. Russell Road , Moseley. IJirrningham.

DISTRICT 4 cEast Midlands). (Otrbl' , l.t ioesm. Xo n banls. Xo u.s.)

M11. \\'. A. SrA1cR, ~1 .\., (G~\\'S), \\'bar:ed31c, llc>nor Ro:id. Jlkelltnn , nri b)'•hln:.

DISTR ICT 5 (Western), (li ereror<I, Wilt•bitt. Glnuecllcr.J

.it. J. K WALKJM (G5JU), 4, Frwchoy Road, Downend , BriSlol.

DISTRICT G (Soulh·Wcstern ). (Com wall, Devon, IJorsct. Somersel.l

Mr. \\' . ll. S vo11otA>1 (G6SY), "Sbemngtoo," Cleveland Road, Too-quay.

DISTRICT 7 (Southern!. (0Jfordsblre. lkrksb1re, Hampsb1rc. Surrey.)

Hr. E. A. DaowA!I (G2KH), 7;,, Woodlands Avcnuc, Coom~. Ncw Malden, Surrey.

DISTRICT 8 (Home Countless. f6ed• .. C&mbs .. llunu and the to .. .,.. or Peterborou;b and

~ewm.arket.)

)lr. ~ J. GMA'lllLD (G:.BQ), 47, W= Road, ~hhon Road C.uubml;e.

DISTRICT 9 ( E3St An11i3). (Korlolk and Suffolk.I

Me. H. W. SAnLn IG:?XS) , " The Warren Farm." Sou th \\'oolton, King's Lynn . l'onolk.

DISTR ICT 10 ISouth Wales and Monmouthl. Mlt. A. J. Fo•SVTll (GGFO) , 29, Stow Par k Avenue, ~cwport, Moo

DISTRICT 11 (North WaluJ. (Aogl<5<:y, Carnarvon. Dcnbiglu hlr<. Fllntsbltc. Merionttn ,

~lon t~nmery. R•dn<>rshlrc.) Ma. D. s. Ml~CllUL (G\\"OAA). "The l'laa11~a." Colwyn Ra y,

Deoblgbsbire.

DISTRICT 12 ILondon North and Htrllord l. (~forth London Postal Dist ricts and ll<rtlorrl, together wilb th•

area known as Korth &llddlcscx.) •tr. s. B UCKISCtlAl< (G6QP), 41, Drunt wlck Park Road. Now

SoUlbgale, N.11. DISTRICT 13 ( London South).

MR. J. B. KZRSllAW (G2WV), 13 . Mont pelier Ro w, Dlaekbeatb S.E.S.

DISTRICT 14 ( Ea1lern1 (East London and l:.sotx.\

~JR. T . A. ST. J o tt s sros tGGUT l, " Normand:tlc," New Dam Lano, Little Hallingbury, Bishopt Stort !ord.

DISTRICT 15 ( London Wull. (West London Poslal Disuicls , Ducks, a nd tbat part of ~liddlcae•

not included in Di• tri• t 12.) MR. H . V Wu.~•" "~"\\ --:~. :,:t!I, O ldfil'icl l .. inr, Sntlhurv ll11l,

Grccn!ord, ~litldlcsc'< ·

DISTRICT 16 1Soulh · ED1l1rn1. (1-:tnt and Sussex)

~lr. W. H. ALLU < (G2UJ), 3 2, Earls R~d . Tunbridge Wtils.

DISTRICT 17 (Mid · Euu. 11.incolm hue and Rulland.)

Mr. \\', Gai rv& !G5GS), " Summerford," New Waltham, Linea. DISTRICT IS (East YOfkshlrO).

(Eut Rid ine and p• rt of Nnrt b R1din11.) To I>< appoinltJ. l:a~ln<li:fe, Co. Durham.

SCOT LANO. Ua. J""'u Husn• IG~l6Z \'), RteordJ Office, 61. C.unpbill

A venue, l...angsid•. G lasgow. NORTH ER N IRELANO.

~lr. A. J. SAsG (GIOTB) , 2:?., Stranmlllls Gardens. Ucllm .

r.-illW MllMUltllS ARR CORD IALLY INVITED TO WRIT& TO 7HEIR LOCAL DISTRICT l{i!PltRS ltNTATtVB.

D ISTR ICT 1 (North-Western),

BI R /(£ N lll.i.-ID.-No reports a re to hand this

monllt, although there i s 1,;onsitle rablc :<ctivily in t ho area. Congratula tions arc

cxlcntkd to 2C \ "K, now G3QX . 2l'Z, 3Q X, 6HQ, R=' ll. G<;L a nd 2AllC arc kno\\'n to be active. 6G1. regrets t hat he \\'ill be unable to carry on as T R. for l he t·n~uing year O\\;ng to pressure of work. I le t hank;; mcmbcn. for thei r past support.

ll/nrk/111rn.-The local group 1s holding its first annual dinner at 9 p.m. on Saturday, }\ovember 19, at The Vee Cross Cafc, Blackburn, at a cost of 2s. p~:r head. \\'ill those "ho intend to be present plcllsc nottfy the T.R . on or before Xo,·embcr JG ? \ 'isi tors wi ll be welcomed.

Congratulation:-. arc offered to 2DAD and 2DKT~ on receiving the calls G3TU and G6\\' ll , respcct ivch ·. 13o th s lll t ions would like reports on their CW :rnd telephony t ransmissions.

/l11mlcy.- G8TD is having rc1narlmb1L• success on '.!8 ~le; . with 137-ft. Zepp, whil8t iiZN linds the W:IEDP aerial very good 011 3.5 J\lc. 2BFll report~ a nd o t her members :ire kno \\'n lo he ac tive.

Httry.-Two meetings w(• re he ld during October, the fi rst at the ORA of the T.R :tn<l t he second a t G8:\L. lt was agreed that future meet ings should be held on the third Tucsd:iv 111 <."ach monlh, but a pcrmancnt meeting pl:lCI.' li:i, yet lo he decided upon. The T.R. would hkc memlx·r' who ar.interestcd to send him a card and he will then forward full particulars in reply as M>On a-; arrangements are completed.

Bury members would ltk(· to congrat ulate the Blackburn Group on their an111vcr,..ary a nd propose to support t he dinner to tlw best of t hei r abili ty.

G'.?C,\ is now \\'.B.E. on 10 \\'alls. I le is active on 1.7 '.\le. a nd would like reports (te lephony or C. W.) from any di8tancc. Other act in- stations

THE T. 6- R. Bl:LLETIS, :'\o\·embcr 193S

~ubmitting report" arc 3CJ, SQS. S:>:F. 8::\L and 2BG F, who is shortly taking his morsc test.

i\I t111rhester.-An attendance or 27 was recorded al the September meeting when C5Yl) gave a n interesting talk on the London Convention and reviewed the Radio and Television Show.

A welcome is extended to G21<Z from Liverpool, also to BRS 3355. 20GV is congratulated on his new call sign. It is understood that the call 2BC is being pirated and members arc asked lo look out for the offending station.

G20I would welcome schedules with any stations on 56 ) le., either C\\", IC\\" or 'phone-his frcqut!ncy " 57, 152 kc. CC.

An attendance or 29 was recorded al the Octobcr meeting, when a sale or disused apparatus occupied the whole of the evening; the sum or £ 1 8s. IOd. wa.~ receh·ed towards the group fund.

A suggestion vital to a_ll those who have ~he interest or this section al heart was made by G3SP. scconclcd bv G5HF that this group should obtain permanent· headquarters somewhere iu or about J\lanchester, where members could meet al any time, day or night, and where constructional a nd testing apparatus could be kept and used for the l><:nefit of all. A radiating permit could, perhaps, he obtained so that the group would have its own " official .. transmitting station. Classes for code practice could be arranged, whilst other ideas of 111terest would no doubt suggest themseh·es. \\'ill all tho~e who are interested in this scheme but who did not attend the October meeting please \Hile 1mmediateh· to G20I, 25, .Boothfield, Winton. Eccles, stating whether they will support it ? lf lhcr can suggest a suitable address in or on lhc outskirts of :Manchester please let llim k now lhc charges for rent a nd rates.

The following sta tions nrc act.ivc on SG Mc. a nd wonltl welcome reports or scheclules: C5YD. 201, 8131, GTL, 5CH, 2RA, 3DA. 2ARC, and 3228. The following are active on other bands: 51-lF, 60)1, 2BDA. 2CDY, 2P)£, 8P\Y, 50L, 50Z, 3BY. 3YC. 2DRH, 3IR, 3)1R, 2F)IC, 21.K, 211\\", 2..\11, 5PX. 3SP, 2918, 5\\'R and 3JZ.

Prts/011.-..\cti\·e stations include C3JH. 3l'J, :ll's, 3QP. 3TX, 5.-\X, 5RU, 5UG, 6FC and 6SQ.

DISTR ICT 2 (North- Eastern)

/)islrict Represe11lntive : L. \\". Parry (GGPY). 1:1, I luddersficld Road, Barnsley.

District Scribe: C. A. Sharp (G61\U), 316, J 'oplar Grove, Great l lorton, Bradford. To11111 Reprcse11!aifoes :

/Jaruslev: T. :\lalkin (G51\1, 5, \\.hile Hill Tcrr:u:e, Dodsworth Road.

/Jrndford: C . .-\. Sharp (GflKt;), as above. /ltilifax: R. P. Pohlmann (2DOR), 138, Skircoat

llloor Road. Jiuddersfielcl: J. Dale (G5VD), 12, Langley

Terrace, Cro5land Road, Oakes. llkfey. J. \\'. Hemingway (GSJD), 17, Thwaites

Avenue, Leetls Hoad. f.tcds: \\'. F. Wilson (BRS23 l 7), -I, Stratford

Strc-el. Leeds. I I. Sluffield : .-\. H. B. Cross (G3F~l. 51, :\fascficld

Road. Wa/1cfield: \\". L. \'. Parker (CGWJ), Chalfontc,

Thornes Ro::id. The Scribe regrets that owing to lack or time

303

during the crisis notes were not forw:lrded last month. T.R ',; arc asked to send in a shurt report or the month's activity in their area in t he form set out in the c i rcu l ~•r sent to them by I lcadquarters with the calls or active stations listc<I in alphabetical order. This should reach lhc Scribe not later than the 25th of the month. T.){.'s arc a lso asked lo sec that a meeting of their nu:mbcrs is held before the end of );ovember, for the purpose or electing a T.H. or confirming the tenure of office of the existing one. Fonns for this purpose were sent to all members last month.

Bamslcy.- Thc winter season opened with a hamfcst at the D.H.'s house. We welcome to the area )lr. Dixon, 2DQL, from Northern Ireland. Acti\·e stations include G2BH, 2\VX, 5DW, 5IV, 5K){. GLZ. GP\', 6XG, 8::\)£, SWF, 2DQL, BRS3068 and 3207.

Bradford. The Bradford Radio Society opened the winter ses.,ion with a very sncccSi.ful lecture a nd dcmonslration on latest television developments given by Mr. 13clleridgc, of the Jforco11i Co. An invitation is extended to all members lo attend a ny of the local meetings which arc held at Cambridge House, 6G, J lorlon Lane, Bradford. The T.H.. (G6KU) will be glad to meet the BHS or A.A. members tht•re. as they are not so well known to him as the tran"nitting members. The syllabu~ up to the end of lhe year is as foll~\\":! :-;'ovcm~r 23, )[r. Garnett {GGXL). Shon \\ave \\ ork, Film Illustrated: Dl·Ccmber 6, )lr. G. A. Brigg:; ( ll'harfedale ll'irdrss ll'11rks). High Quali t r Reproduction; December 20, i\lr. Bateman (G6BX), :\ .C. Practice and Theory (Elementarv).

G6l\lC and GXL are' erecti ng rotating beam aeria ls for 28 Mc. GGQS has now W.A.S. and is <t member of lhc DX. Cenlury Club. C:()Xl. scored 3,7:15 in the Vl\; ZL contest with 52 contacts.

There will he a meeting of R.S.G.ll. members at the T.R.'s QHA, :J IG, Poplar Grove, Grc:u l lorlon, on Saturday, November 19, at 7 p.m. Please send a card if you arc coming.

Halifa-r.- 1..ocal members are a,.kcd to forward reports to the new T.R., :\lr. R . I'. Pohlmann and to gi\·e him tbeir support .

Sheffield. Al a meeting on Octobcr Cl, C2J Y resigned from lhc position of T.R., and G:JFX was appointed in his stead. Best tha nks arc recorded to the retiring T.R., who has worked hard for the last three years in keeping his a rea active. \\·e welcome to the town C30 K. who is second operator to G5YC. Stations acti\·e include: (;2AS, 2JY, 2JI, 3FX, STO, 6LF, SJP, 2BXA and 2DTJ.

H11ddersfield.-At the last meeting al G5\·D, it was decidl'd to form a local QRP 1.75 )le. circle. \\"ill all interested write to 5\"D ? (G6!\.U, Bradford, will QSO any Sunda\· morning on 'phone or c.w., 1100 to 1:101) c;.:\t:r:J. C8FO has worked \ 'Ot \ " on 7 )le. using 4 watts. G8GU, ST;\l and SOF report acti\·c.

Leeds.-Thc T.R., who is back in the town again, after spending the :;ummer in District .9. reports that no nolt's h:we heen recen·ed by lum, wh1lsl no interest has l><:cn ~hown in the scheme published in the Jmw Jkr.1.1ffr:-:. Local mcmbi.•rs arc asked to send him tll•lails or their activities.

lll//el' 111111 Wnkeficld.-\Vbat about some notes, plt!asc ·? Scvl•ral sl,Ltious are act ive.

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DISTRICT 3 (W est Midl a nds)

Cove11try.-Thc C.A.H.S. have starled their winter programmt', and the Committee would like to ca lJ local members' attention to this fact, as the attendances at lht• weekly meetings arc not as good as they !thoulcl bt·.

Actention is also drawn to the C.A.R.S. Annual Danner which is to be held at the King's Head Hotel, on \\'edne~da\·, Xovember 23. As it was fcl t in pre,·ious year-..' that 5s. was a Ii ttle on ll1e expensive side ticket:. tlll'• year "ill be 3~. 6d. The T.R. in,·ites all members of R.S.G.B. in Coventry to allend this !unc tion.

At the meeting on December 6 a talk will be given by C2LU on ·· Amateur Jfodio as a Hobby."

C6YV a nd 5PP arc both operating on 56 i\lc . with crys tal control.

Ca1111ock.-C6SW has a new .JO-foot lattice mast (rom which he intendi; to support a Johnson"' Q " bc:im for 14 Mc. 2YV has received SS from Algiers on his 7 Mc. 'phone. but is dissatisfied vdth his rig and intends rebuilding with a 53-59-46's fo r all bands. 2FAP has built;\ nt·w transmitter (47-46-46) :i nd is now wailini; for his full call. 2FAH is rchui lding.

The Cannock nnd J)is trict Amateur Haclio Cluh !ms made good progn·s~ and new members wi ll be cordially welcomed. A s low morse practice was held on Sunday. October 9.

THE T. cS- /?. BU!.LF.TJ.Y, Xo,·embl.'r 1938.

Staffordsliiir.· GSFQ is active and has W .A.C. on 14 :llc. l·fo tts(.•s GLG-GL6-T20 with :i. WSJK beam. Congratulations to 5Lj of Sutton Coldfie ld, who has WAC a nd WHE on 1-1 and 28 :lk. 'phone. lie fincL~ a Johnson "<J" superior to an l'Xtended Zepp for omni-din:ctional transmittini:

Stations acuvc 111clu<le G2.\1~. 21.H, 2\\"D, 5BJ, 5SS, 5\")[ anil 61.)1., and reports from them would be g reatly appreciated.

A meeting of Staflor<l:;hire amateur~ 1" being considered. Tho'(' mtcrl.'Ste<l ~hould pll'a'<' communicate with till' Scribe : G. )l. Whitchou>e, G2Y\', Trumwyn Hou"<" Cannock.

DISTR ICT 4 ( East Midlands) . The meeting al N"otlingham on October 23 pro

duced an attcndanCl' of 30 members a nd rno~t parts of the District were represented. Afi cr lea and a short business sess ion. GSM\\' opcn1o1d a discussion on QRP versus <} RO and many different opinions were expressed.

Tt was decided tha t the 1wxt mcetinH ~houhl be a t Leicester a nd arrangement~ ha\'e now bc<'n mad<' for this to take place on Sunday. :'\ovcmbcr 20, at the Royal I lotcl, Town Hall Square, at 3.30 p .m . It is particularly hoped that. thi" meeting will att.ract memlH:rs from Northampton. A Junk sale will take place a nd everyone is invitc•d to hring surplus gear for dii.po">al. A talk is a lso to be arranged.

FORTHCOMING EVENTS Xo\'. 16 Distract 1-1 ( l ~,,t Essex St·ction}.

S p.m. at G2KH, "Emrick." I lampton Gardens, Prittlewt'll.

17 D1:-tract 6 (Torquar Section). S p.m., al GSSY. "Sherring ton " Clc,·eland Hoad. Torquay.

IS Dbtricl 12, 7.30 p.m., at the Orphcum Cinema, Temple Fortunt', .:-.'. \\'. 11. Lecture by G2~0 : " ~lodern Communication Receiver;;. "

22 D1!>trict 14 (East London S<·ctaon). 7.30 pm , al 2D JI, 23, )lornjngton Hoad, Chinf(ford, E.4.

23 Scotla nd " E" District, 7.30 p.m .. 111 Fleury 2\lcng's, 48, :t\ewmarket Str<'l'l, Ayr. Lecture by D. 1.nrnh. Esq. (GM2UU) : subject, ·· At1rials."

23 District :l C.A.R.S. Dinner, 7 .30 p.m., al the l\ing's llead Hotel, Coventry. Tickds, 3s. Gd. each.

2:i London i\lcclang at the I.E.E. Commence 6 45 p.m. Tea al 6 p.m. L<•cturc and Demonstration b,· K . Froi.t, Esq., Standard Telephones and Cables, Ltd. Subject, " RcC<•nt Valvt· Developments."

24 District 1-1 (Brentwood Section), S p.m .. a t G3JW, 44, Weald Road, Brentwood.

24 District 13 (Central Areas), S p.m., at Brotherhood Hall, \\'est >'orwood.

24 District 6 (Exeter Section), S p m .. at :1, 01:1. ·,, Faeld, Exeter.

--

~o,·. 27 D1-..tmt 11 , 1-..trin 9. :Ill-et at 215 p.m out-..ult• :\orwich G.P.O.

30 Scotland " A" District. 7.311 p .m, in Room " A," I nslitulion of Engml'•·rs and Shipbuil<IC'rs, :19, Elmhank Crescent, (:la-1rnw.

Dec. rn,.,trkt 14 (Colchc!>ter Section). 7.30 p.m.. at G81'Z, 19-2 1 . • \ rtillerv Ho.HI, Coklu:..,ter •

2 Dhtratt ~. mt·•·tm~ in Cambradg,· 4 Di-..trict 1-1, 3 p.m.. at GHl'T.

" Xormandale, " Little 1-1.l!hng-bury, 1wa r Bishops S tortforrl.

7 • District I (.\la nchcstcr Section). i.30 p. m .. a t llrook'"s Ca ft!, 1, J Iii ton Stret·t , off Oldham Street. Manchester. Tall< hy G60'M.

7 S.l4,l>.Jt1'.S.. 8 p. m ., at l3rolht:> rhoocl I !all, West Xorwood.

8 Di<tnct <i (Exeter Section). S pm .. at :1. D1x's Field, Exc·tcr.

11 Da-trict 7. 2.30 p.m.. al G2\"1., " Ht•<lholm." \\'alton-on-tht·-Hill, Tadworth, Surrer. Di..,play of R .S.G. B. Films.

14 • Dii.tract 15, 7.30 p.m., at 2DFJ. 2:lH, 1..adbrok•· Grove, Xorth l\l'll· ..,i ng ton, \\' , IO.

15 District Ill. 8 p.m .. at (;lobe llotcl, Duke S t reet , Cardiff.

15 01;,trict 6 (Torquay Section), S p.m, at C5SY, "Sherrington," Ckwland lfoad, Torquay.

• Sale of disu,,·d apparatus :i.t thc,,e nwl'tang..,

THE T. <£.. R. BULLET!.\', Xovcmbcr 1938.

Preliminary arrangements arc in hand for the December mceling, which will take place at Mansfield.

Mansfield.-Rcgular monthly meetings arc being con, ·ened b\· CSSA, the T.R. At lhc October m~-cting, beid at the Swan Hotel, )lansficld, 15 members were present and a further meeting was arranged to take place on Xovcmber (i. CSSA will supply details of future a rrangements lo any member residing in this area.

The D.R will be glad lo rccciw any further nominations for T.R.'s. Forms may he sent di rect to him or handed in at the Leicester ml'eling.

DISTR ICT 6 (W estern) The chief item of int erest during October was the

Conventionette held at \\'cslon-supcr-)lare, the attendance at which was ,·ery good, everything considered. A full account appears elsewhere.

OH LW\V was a visito r welcomed to the October meeting in B ristol, a n a utographed copy of the " llelping Hand to Amateur Radio " being presented to him as a record o f his visit.

Later in the month a party visited Grid House, Bristol, the south-west headquarters of the Grid S}'Slem. The method of communication between the various stations, whose " call signs " consist of audio notes of different frcqucncic:., was particularly interesting. A ,·isit has been arranged for No,·cmber to Broadcasting Hou~c. HriMol.

Although few reports have been received, the usual stations in and around the town arc active.

The T.R. for Gloucester, C5JH, reports that there arc a number of prospecti\'c new members in the town. A station using lhe call C3\\'D, who gives his QRA as Cloucc:stcr, is active on 1.7 :\Ic. but is probably a pirate. Will the owner of tllis ea 11 plea~e wrilc G5 j U ?

GSJQ of Bath had his bl•:im at•rial blown down recently but is agai n active on :?8 Mc. and, in common with SDX, is obtaining good results. 21\\' has applied for a 28 )le. licence. SUW bas returned to Balh and is active. The peculiar noise reported in last month's note~ has been less in c\idence. Can any member supply an explanation concerning 1t-. origin ?

Is lhere any activity in Chcilenh:un ?

DISTRICT 6 (South W estern) ,\·ort/1 De11011.-Congralulations lo GSUS who,

with the receip t of one more verilic:ition, will be able to claim his W.B.E. 14 Mc. C. W. certificate. /\ piece of good operating resulted in a OSO with Pl\3ID1 recently, during one o f his tea-time sessions on 1-1 )Le. 6C:\l has finally discarded dry 11.T. for a ~upply t•ia wind-gencralor and motorgcneralor. 3GI I and 3BO ha,·e been granted their 25 watt pcrmib. C3:U!, 2ID, 2DO\\', and 2FKF report active.

Ta1mto11.-Xo meeting was held last month owing to the Con\'entioncttc at \V(•;,ton taking place on lhe date chosen. Congr:llulations to 2BXZ, now G3SB, on obtaining 111~ full permit. BRS2027 is expecting his A.:\. liccnc1·.

Exe/er.-It ha<; been decided that all future Exeter mectmgs will be held twice monthly on the second and fourth Thursdays, at ~o. :1. Dix's Field :1s before. All stations report active and lhe usual Morse classes arc held at each meeting following an hour's discussion of queries ra ised hy mcm bers and ;,cnt to the T.R. a few days earlier. This gives

305

lime for any necessary reference to text-books, so that the queries, when they come up for discussion, can be satisfactorily se ttled. \Viii Exeler members please note ?

Plymo11th.-Those present at the lirst winter meeting of the Plymouth area. held at CSPN, were G2llX, 3TX, SllF, 8PX, 2DLJ, BRS293:!, 2997 and )lr. Kendall, a prospective member. Discussion took place regarding activities since the last meeting, and CSL-'.N and BRS932 described lhcir efforts at mast erection. Congratulations to G3TX on receiving his full call. G21 LX is considering the purcha.'\c of a commercial receiver. (That would be a fall from grace !-D.R.) SllF is working a number of regular schedules, and BRS2997 is still ha,ing trouble \\ith his receiver.

·n1c next meeting \\ill be held at GSllF on )fonday, Xovcmber 1-1. but as the BULLl>TIN will probably be issued after that date, the O.R hopes that in future the dates of meetings can bo arranged for lwo months ahead, so that a notice may be inserted under " Forthcoming Events."

Torq11ay.-The fi rst meeting o f the winter sea~o11 was held at GSSY on October 20. Those pM.cnt were C3ID, 3JD, 3HW, 5SY. 5YR. 6H.F, .BHS3171, 3392, 3-101, and a prospecti,·e member from Totnes. A number of subjects were ch~cus~ed. and in particular, members were urged to make proper use of lhe \-arious nomination and ballot forms sent oul from lime to time in the Bu1.Li:T1N. Improper use of the DX bands was also dbcnssed. and those present agreed that it should be considered bad form to use these for purely local tests and contacts.

ll w;1s decided that at forthcoming meeting~ mcmbt•rs should. in turn. prepare one particular topic for discussion, not necessarily in the form of a lecture, but for general consideration after a preliminary introduction.

G:JI IW was presented with the C2C£ 56 Mc. Challenge Cup in recognition of his good work on 56 )le. during the past year, and especially for his contacts with C6FO in South \\·arcs. This cup ha:>, unlil this year, been awarded on lhe result:. of one or more· 56 )le. field da,· contcstS, but as lhere were so few members trus ~:ear holding 56 )le. portable permits, it was decided to award 1l for lhe year's work.

It is hoped lo hold a combined meeting of the Torquay and :Exeter membership, at Torquay, in janu:iry, at which the latest R.S.G.D. fi lms wi ll be shown.

D ISTR ICT 7 (Southern) There is an important change for the December

meeting. The ::-.r.F.J). films are to be shown and a-; these ar<' not available for the first Sunday in the month, the meeting has been postponed until the second Sunday, i.e., December 1 L. This will be at G2\:L's QRA, (nearest station Tadworth, S R.)

G11ildford.-G3HlI, SIX. SUG, arc acl1V(' on L-1 )le., and GGS, Gu.-, 5\VP on 28 :llc.

Kingslo11.-Congratulalions to 2DOP who b now C3\'K C5LC ho~s lO be on the air i;hortly GSllA has taken an appointment with the G.P O and now becomes G:\UlHA. The follow111g arc: known lo be acli,·e- G2GK, 3AY, 3BF, 3DZ, 3:\lF, 30R, 3VK, SLC, 5MA, 6~1B. 6PK, 81!A, 811Y, 85~1. STX, 2CXI. 2DOK, BRS3297.

Poi·tsmoutlt .- Thc programme of lectures for the South I !a nts R.T.S. had to be slightly changt'<I owing

306

to unforeseen circninstances, and 2CBL came to the rescue by giving his lecture on " Sunspots " at the October meeting. This proved to be of great interest to all present; a :,hort discussion followed \~'~HQA, "".ho was. present at the meeting, also v1~1ted 2A \\ C. GS\\ C. and the T.R. during hjs stay at Portsmouth. 2CDL has passed his morse test, and now awaits his call. )lost local stations aro active.

f) ISTR ICT 8 (Ho m e Counties) A " CTY successful Djstrict ;\leeting was held at

the \\'affie Cafc, Petty Cury, Cambridge, on :'>londa\', October 3, when sixteen member:; were presen't. The change of meeting place ~cemrd to meet with general approval. During the evening the D.R. asked :'>lr. Gerald jeapes (G2X\ ' ) to accept a Ferranti 0- 1 milliamp. meter (~ubscribed for by the District membership) in recognition of his untiring sen·ice on their behalf.

A most interesting talk on Transformer Winding was given by ;\lr. 11. \\'. Scott (G5DR), who was warmly congratulated on get ting these montl1ly talks going.

Reports arc ~cant~-, especially from the Bedford· shire area. ln Cambridge C5JO has been testing on 28 )le., 2XV reports salisfaclory results w'ith his new thrrc-clement beam, while 50V, still using ~is r!1ombic._ works e.as~wanls with regularity. :iDR 1s applymg the fimshmg touches to his rotary beam, 5BQ has now \\'.A.C. on phone. SS\." is also acti\'I!.

The R.S.G.B. films will be shown at the Chesterton Senior School, Gilbert Road, Cambridge, on December 2, when an invitation i!' c•xtendcd to XYL's. YL's and friends. There will be ample accommodation for all.

D lST R lCT 9 ( East A nglia). .\ Distract .\lc..-eting will le held 111 Xorwich on

Sunday. ~ovcmber 27, which the D.H.. asks all members to try and attend. The meeting-place i~ ~omich G.l'.O., 2.15 p.m. sharp.

Ipswich. 1\ cti\'ity generally has been on the wane. Si\l U has been concentrating on 28 )le. with considerable success ; 6TI will shortly be heard on that band. 30J has migrated to 1.7 :\le.; 2JD reports better DX with higher masts ; 3XQ has completed a separate tran~m1tler for 1-1 :\le. SKB is using a single 6L6 while rebuilding. SIS has not been heard lately, bul is presumed :icth·e. 2A~ is to test on 28 and 56 ;\le.

Local members congratulate their T.R. and his wife on the birth of a junior Op.

Great Yar111011tl:.- Acth·ity is generally very high. The local club is going ahead well and lectures are given c,·ery Friday night. G3HW is acli\'e on 7 :\le. BHS3256 has applied for an A.A. licence. . Lotustoft Area.-G5QO is now testing daalv on

3.5 and 7 .\le. telephony. These tests a.re solely concerned with propagation anrl reports from all quarters will be very welcome. 31U.;:, of Beccles. is now on 7 .\le. telephony and would welcome contacts and reports. Congratulations to J\lr. Leader. of Bungay, who is now G3UT and testing Oil 1-1 :\le.

Scribe's Sote.-lt is some lime since reports were received from C2UT. 2XS, 31:\', 5CF. SUD, SFL, and many A.A. and B.H.S. members. Kindly inform your T.R. of your activities. so that he may let the Scribe have a report by the 25th of each

THE T. 6- R. BULLET/.\', Xovember 1!1:.11>.

month. In ca~es where there is not a T.R appointed reports may be sent direct lo G5QO.

DISTR ICT 10 (South Wales and Monmouthshire)

The outstanding e\'ent of th(• month was the \\'estern Districts ?.Iceting, held at vVcston on October 9. The meeting drew nearly sixty members from all parts of 1'\os. 5. G and 10 Districts and was a great success, attributable in no little· degree to lhe efforts of the Weston group and G5JU, D.H. ofXo. 5 District. who made themseh·cs r"~ponsible for the arrangc•mcnt ....

Thoi;e prt'~ent from Xo. 10 wen· 2.13G, 2JL. 2KC. 2UH, 2XZ, 3AJ._ 5Br. 6FO, 8A:'ll, SNP, SUll, SWU, 2BQB and 213VF, :;omc of whom travelled from Cardiff to Weston by air. This turned out to be a very convenient way of making lhc journey and may be 0 1w reason why the South Wales people supported a proposal from the other side that \\'eston bt· recognised as a regular centre for Pro\'incial District ;\[eetings. though they will normally be held at a more convenient time of year. "'e missed -<>me expected Swansea faces, but it is only fair to say that it would h:we been a very difficu lt journey for them.

T.l{. nomiMlions have come in from several areas and the official announcement:. will be made in due course.

Cardih'.- The regular R.S.G.B. meeting was held on October 13, attended by 2BG. 2t:H, 2XZ. 3.AJ, 5XX, SA:\!, SXP, St:H, 8\\T, 2BQB, 2DUF, 2CPA. 2011:'11, 2DOZ, 2DSD and 2DXS. A new call in t11is ~roup is G3\IL (rx-2C l'A), whom we welcome.

Blackwood.- Activity keeps up here and GGBK \\'i ll be arnrnging regular meetings <luring the winter at which it is hoped to sec olhcr members from out!'idc the area.

.\'ewporl.· Some new membership applications arc pending :tml when they materialise, G2JL must take the credit. J-le has been most active in encouraging newcomers and his station is invaded every Sunday morning.

The D.H. looks forward to allcncling meetings in all centres in the District, with a successful season for e"eryone. Jn particular, it is hoped to sec more acti\'ity on our lesser-used bands, 28 and 56 l\Jc. \\'c need not mention 1.7 :\le. in this connection, as District 10 has always been strong for this band and several or the DX men can bc heard working locally at Uw week-ends-which is a ll to t he good anrl as it should be. ·

DISTRICT 11 (Nort h W ales).

There was an attendance of l.J at the meetin~ on October 23. The T. H. scheme was iliscussed, but it was decided that the district had no town in which the number of members merited the election of a T.H. ll was t herefore decided that County Reprcscntati\'es be appointed for Caernarvon~hire, Denbighshire, and Flintshire. The following were proposed and una nimously approved as rcprcsentati"cs of their respective counties : j . W. B. £\'ans (G\\'3GL), \\'. J ones (C \\'601.:) and E. G. Foulkes (G\\'5Fli).

The new l<.A.F. Ci\'ilian \\'ireless Reserve is creating considerable interest in the district. The D.H. has been appointed a Hegional Controller in

Tl/E T. e. R. BULLETT.\', ~o,ember 1938.

conn1.-cl1on with the scheme. .\l lhc next meetin~ hi! will g1,·e a short talk explaming' the objects of the Heserve, a nd will be plea,ed to g1\e any a1hice he can concerning enrolment.

G WGO K has been having 56 .\le. contacts with CSl\!Q (·10 miles). receiving S8-9 rllporl s. This is particularly meritoriou~ in view nf t li e fact that 601( is prac tically at sea level a nd in a very badly i.crnencd location. 6AA has hccn in regular 56 ::\k. communication from his home s tat ion \\'ilh G6SQ (65 miles) and G2I;..< (50 miles). Both 60K. and 6AA would appreciate schedules on th1~ band. They arc able to recei,·e C\\' in acld1t1on to phone and :\IC\\' •

\\.ill members cndca\·our to hnni.: lo future mcellngs any new ,-ah-es and appar.\lu' they may ha,·c purcha.;cd in order to promme cl1~cus,ion

DI ST R ICT 12 (London North and He r tfo r d)

T he October meeting was lu! lll i1s usua l at the Orphonm Cinema, but the ta lk by tl li . Parr did not lake place as he was una ble to lw present. The D. H. look lhe chair and indted <liscu ~si ons on anv su b)ect of interest. ,

'I here has been some dou bl as to whether we l>hall be able to continue our 1111•e tingi. al the Orpheum. but arrangements have l>1:en made to hold the Xo,·ember meeting there and , 'hould it be 11\.'Ce!>sary lo change e,·entually, due notice will be given.

The Xovember mectini:: ~hould bc or special mterc~l to all members a:. :\lr. 11. R •• \dams. C2~0. or Wrbb'.~ Radio, will be bringmi; along some of the la test communication receivers.

GGLL has been active on 56 ,\le. a nd has rccch ·ed a n S·I 1'1:port from Clact.on. Il l! was us ing a 6L6 doubler with a n output of ·I watts. 81\ Y lost t he :JO. ft. mast front his roof during t li ll recent gale. Fortun:\lely no damage was done and he says now that il is rather a good thing as he \\'ill be able to put up a ne\\' beam array!

ll't/w1•11.-The fir5t meetm~ or the Central Herts l{roup during the present :.cason wa, held on October 7 at the QR.-\ of GGX~. e1~hl members bemg pre,ent. includini; CSTK, \\'ho cycled 7 miles from Sl. .\!bans. XX demon,,lrall.'d t he·· ::\lurphy .. .\52 push-button receiver, clauned to be the only commercial broadcast set with band-,pread tuning . Aclh•1t1es : GSTK. St. Albans, \\'Orks U.S. on 7 :\le., while 21)\\', an old-timer in that city. is hea rd again after m:rny years. SVJ is boliovcd LO have moved thoro but no details are a vailahl.;, In Ha rpenden G:IJ X has W .. \ .C. with 10 watts, hut his Hi\l.E69 tempi~ him to call more lhan he ran work ! His next ·door neighbour is G6\ 'S. bul as the latter is inactive no problems of mutual <)H::\l h ;:we yet anscn. In \\'elwYn Garden C1t1· ··Old Ireland." C2C:\, starts up a·fter a long <2wi· G6XX. a hundred yards away from him (and a hundred watts !) i:ompares Sj K beam and 13:J.fl. end-on. G'.!\"X puulcs O\·er an aerial in the back garden that bas lO be fed from a room at the front of the house, and G:\ lSl'.\l 1s welcomed from Scotland \l \\'ehn·n villag'c C5U:\l. aggrieved at the frivolous 'pho-ue Q IC\l on :.1.5 :\le .. concentrates 0 11 1.75 :\k. break-in work with C. \\'.

D ISTR ICT 13 (Lon don South) The District meeting held .Lt 1'\urwood on

October 27 wa;; a great success a ml t he1 e was a n

307

attendance of -14. It is truly cncourag1n!{ to '>CC such an excellent turn-out and we do mo-.L smcerely thank a ll tho-.e who were present. Owmg to an unfortunate m1l>take the date of the mcctini-: appeared irt the HuL.L.ETJN as October 20 and the D . I< . was then·fore obliged to send out over 100 postcarcls rec t ifying the error. H<>wC\'CI'. the la r1;e gathering seemed to indicate l hat the carcls had no t been sent in ,·ain ! A very reasomdJlc sum was added lo the Dis trict Fund and it is hopecl to dispose of some of lhe surplus junk at a later date.

\ 'anous report" ba,·e been recei,·ecl this month but nothmi: of outstanding interest C5G ll 1s busy cn.:Cllll)! h1., gear and was interested to hear \ 'S6.\ 0 on October 18 ; 3CT i~ expcrimenllllJ.: with a H :\le. band ,·ariable directional aerial and reports that there arc now three am.1.leurs 111 the R.\ . ::\le .. s. 2GZ is obtainin~ excellent resu l l~ fro111 his ne"' ·•doublet " a nd has now worked ZEl.Jl. :ICU is engaged in construc ting gear for the 28 ~le . b:uul. 2ZQ s till finds lime to work DX in spite of his C. W. l~ . act ivities. 2WV was pleased to contact OW5AQ 011 14 Mc.

213MI l is \\'Orking hard to organise some local gatherings in lbc W imbledon area ancl wo hope that all those in that neighbourhood \\'Ill give him their ~upporl. Details of the next meeting will be circulated 111 due course.

:\lay we conclude by requesting lhal all reports be for\\'arded to the T.R. each month. Each T . H. is supposed to report e,·ery month to the D. I{. and the reports would thus be automatically tabulatccl under their respecti\"C a reas.

D IST R ICT 14 (Eastern)

Easl l !ss1-.1'. - J\l the October mccliug h<1ld at CGCT Westc liff-on-Sca the attendance was 18, including cx-VU2FT. G5XI was nominated T.R. for the coming year in succession to G2LC, who wished lo be re lieved at once owing to prcs~ure of work in other directions. .-\ Yote of thanks was passed to G2LC for the good work he has done fo r the area since he took o,·e r the work lrom G51J K t'>\'O years ago. The R.:\.F. Civilian Wireless Resen ·e \\'as the ~ubject of much discus~1011 This area has now four members enrolled anti others are likely to join.

Due to the sm:cess of the last Q H.1' contes t. it has bc<.·n decided lo hold another in the near future.

G5V~) will be active again shortly after a l<>ng spell of s ih:nct'. 3TS has been on 7 ~le. with one wall input and has been doing well.

13renlwood. - C3LA has been uomina lecl to take over as T .K for Brentwood in place of \.3:\[V. Congratulations to '.!CRJ now G3VD \\'hO is alread\' active on 7 ':\le_ 3]\\' is usin~ .1 new Class :. A" modulator. SRC and 3::\l\' arc ac tive on 7 :\le. 2A Tl: has been grinding cry:,tals.

Che/111sforil.-\,5R\\' is again on 3 5 :\le. 'phone. 3BS is Lakins: a Candler course with a view to 30 w.p.m. I 5R\. has received his DX Century Club certificate. 2KG is working on a beam aerial. 81\ I) active but has not reported. GLB is shortly to he [married.

Hast /.0111L<m.-T hc October meeting was held at G5J\J<, \Vc)()((fonl, when the C.W. H.cservo was discussed . G:IKZ attended his firs t meeting. 20] l ha~ appli l•d for his full call. G:JN F (XZ2EM) of Snarcsbmok C'Xpects to return to Burma in

~108

CHATS

@ (N o. 2 of a series).

Arclcles. appear from time lO time in the various " ham " maaa.zlnes 1fv1n1 Instructions. for rc·&rindinc cryuats. When you rind that the frequency of your favourite crystal is covered by a high-power phone carrier. the temptation is very stronc to make a dive for the plate 1lus and knife powder,

or whatever else It waJ you uw In eh.at article last month. I( It I• a 1.7 Mc. or • 3.S Mc. plate on which you Intend to operate you will probably be lucky, but II you arc trylne to re-erind a 7 Mc. pfuc. the chances ire a hundred to one chit your crystal will eventually be returned to the manuf.acturcrs with 1 tca.rlul lctcor ukln& them to do whu they an to retrieve lu 01cill.uing propertle.s. but with the be-.st will in the world the m1nub.cturcrs an not do much with a crysul that has been Inaccurately rc-iround and h alrudy within a lew kilocycles or the H.F. ode• ol the b•nd !

Honestly, re·erlndinc a 7 Mc. cryn~I Is • spcci•llst ·s job. •nd porh•ps the followlns llcures will explain why this 11 so. A 7 Mc. X cut cry11al Is approximately 16 thousandths ol •n Inch thick, and to obtain the maximum outpu t must be ar·ound to an accuracy of better than one ten thous:and th part of an Inch. To move the frequency 6kc. higher the amount to be rubbed off the crynal Is less than one·hundrcd thouundth part ol an Inch (.00001 in.). 11 you take only • fraction more oll the edcos or the crynal than the centre, the cryst•I will stop oscillating •ltogcthcr, •nd I can assure you that to grind this amount off :accurately Is not cuy, even lor an export. So please do take my advice, a.nd, U you must have the frequency altered, give the man ufacrnrers i ch:ance to do It properly, and return the crystal to them bolo rc you have ruined It youncll,

It will be cheaper In the lone run, u the char;e will be qu it e sm•ll. For eumple. Q.C.C. charse 2 /6 lor re·crlndi n~ • cryn•I to • hleher frequency In the same band. and this charce Includes recaJibntlon and the Issue of a new tut conlfkate.

~ A DEDMAN (GlNH~ Ad•crt11cmen1of1M QUAATZ CRYSTAL CO •• l TO .• Now Molden. Surrey

'GW3GL Every thing in Raclio for the

Amateur. WE SPECIALISE IN SU PPL YING COMPONENTS FOR SHORT-WAVE WORK.

Call or send us your enquiries. LARGE STOCKS CARRIED.

by post promp!ly attended - -Orders to. - -- -THEJAPIARY , CONWAY, N . WALES

THE T . <!>- /?. /Jl ' J. l. H.TI.\', );o,·ember 1938.

Ex-lBGG . .. Now Gl CR . . . by way of a thank-offering has a few variable air-gap crystal holders, suitable for frequency variation with AT & BT cut crystals,

at 10 / -

AT & BT cut crysta ls are available at the usual price. as arc pressure·type holders.

RADIO CONSTRUCTION SERVICE 293, ROTHB U RY TERR., N EW CASTLE-ON·TYNE, 6.

CRYSTAL CONTROL FOR ALL-

BAND. ACCURACY. (a) l ·75 J\k. 16/6 ± l kc. .. 3·5 a nd 7 Mc. 15/- ± 2 kc. .. 14 Mc. 30/- ± 5 kc.

(b) 100 kc. 15/6 ± O· I kc. Temp. Cocfl. (a)-(23 X 101)

(b)- ( s x 101)

Enclon d llo ldcrs, pluit-ln type. s ullnbl e nil bnnd9, ll/6

BROOKES MEASURING TOOLS, 51-53, Church Street, Greenwich, London, S. E.1 0

T.I. : Gr.enwKh 1828

TO KEEP IN TOUCH-w ith all the latest developments in short-wave radio.

take RAD 10 the World"s finest Ham Magazine. Don't be disappointed. Subscribe to-day.

Annual subscription. 10 Issues 14 j6

European Agent : Two years, 24 /6.

N . E. READ, 24, Church St., Oswest.ry.

TU NING COILS

I. F. TRANSFORMERS

L. F. TRANSFORMERS

L. F. CHOKES

MAINS T RANSFORM ERS VARIABLE POWER RESISTANC ES THERMAL DELAY SWITC H

Write for Cauloaue No. 13 &ivin& free information or V~rley com ponenu .

V A RLEY (Oliver Pell Control Ltd.), ~ CAMBRIDGE ROW, WOOLW ICH, LONDON , S.E.18

J"HE T. 6- R. Bl:l.LETI.\", Xo,·ember 1938.

January. .Members attending the rm·tlling at GHUT, Little Ha ll inghury , wi ll he met hy a car at ~pellbrook, the Green Line s top.

D IST R ICT 15 (London West, Midd lesex a nd B u cki ngham shi re ).

A highly ~uccessful meeting of the Dist.rict Committee ancl T.H ·, was held on October 12, \\hen details of the forthcoming sca....on's meetings were worked out.

The District Dinn,•r and Social cv .. ning was fixed for January 7, 1939, when dress will be optional Ladies of coursl· arc invite<!, and ticketS C<hliog 5s. t;d. cach can h<' obtained from any T.R. or the Social Committct' . The venue, which is to bdhe Park Hoyal Hot1•l, can be reached quilt• easily from any part of tht> di~trict. 1l is hopv<l that ewryone will make a wry great effort to be there.

ll is nece~~:in· for T lt.'s to be nominawd for all part s of the J>1s.trict and the D .H.. would like to see extra ones pul forward for the extreme nor! h part of :lliddlcscx (around Edgware). the south p;irt of "''-'"t London, Houn~low and Slough. Thb would help in keeping mC'mbt·rs in those parts together. Please see to it that ~·ou are reprC"senl1•cl for the forthcoming year by ~t·nding nominations lo the DR. at once

It is hopt'd lhat di-trict meetmg:> will he spread round the di~i.rict Ill future and offers of help in findi ng suitabh: places lo meet would be welcome. Talks and ~hort papers arc required. and assist.ance would be apprt•ciat(•d hr all T.R.'s

Soul/I .lliddlcsex.-C:rng and 3JG report. Also active a re G2Kl, 2~~. 2VV, ~!BQ, :JGQ. :lj(;, 6GB, 8 11N, SIP.

S orth JI 1ddhsex.-G5SR and G6\\" :\ active, t he latter, who b using a temporarr aerial, works\\. \\ell on 28 '.\le. Good results arc obtain!'d in spite of an east·west aerial only two feet off the ground at the far end.

Hucks.-G6]K, 2B.\O and 2B\"X active. Some complaints lrn.v1· reached the D.R. regarding

duplex telephony working within the arc;\ which goes on for considerable periods. This is lo be deplored if it interferes with other members .

.:-rew membc:f!> who ha,·e joined thl• district recently arc welcomed, and we shall be pleased to i.cc them at meetings 111 the near future. We were ple,1sed to haw \"KSRX with us at the la;;l mceting and hope he has a good ,·oyage back home.

D IST R ICT 16 (South Eastern)

The D.R. has been pleased lo rec!'i\'e several T. l{. nominations and trusts that the l)btric t will have a full complement of T.R.'s m 1939.

Bri:;/z/011 aud //ot·e.-The .\nnuaJ General Meeting of the local ~oc1ct\" was held on October 6, and the Secretary's rt'pon ,howed that good progress is being made. After tlw usual busine:.s had been concluded lhe R.S.C.B. films were shown, and much appreciated. 2CTO, the T.R, now awaits his full call. The following reporl active: G2RU, 3 11 P, 3JF, 31-:J, 6CY, GR.\£, SAC, SOQ.

IJromley and Disl11cl.-The fin.t meeting of the seal>On was held on October 21 at 2BSO, and a ,·erv enjoyable time was had by all. Arrangements were made to hold monthly meetings during the coming seaM>n, and a program of discu......,,ions was prepared. The nex't meeting will be on :\o,·embcr 2S, at

309

8.IS p. 111., at. the QRA of 2A\ ·r, 75, High Stn•ot, Brornky.

Ea~lbo11me.-Tltc following s tations report acth·c : (;2,\ 0 (1.7, 28 and SG :llc.) , 3AT. 3CX. SB\\" and SIH ( 1.7 and 3.5 ~le.).

Graveswd.- The D.R. opened the lecture seal>On on October 10 with a talk on S6 '.\le. The meeting was well attended, and considerable interes t was shown m 2Uj's recei,·e r and three-stage transmitter which were on view. A;, far as possible, lectures will be given once a. month during the coming scaso11, a11d among those nlrcady booked is one by :IIr. Nixon, of G .E.C., on " Speech Amplifiers. " Activity: G2IZ, 2KL, 2T:\, SIL, SSU, GBQ. 6PG. 6VC and 2BDL.

Clziclzcsler and Dislricl. Thirtv members of the Sussex Short \ Va,·e and TcleYfsion Club ,·isited .\lurphy Uadio on October 12. Acth;t:· is mo~tlr on 28 and S6 '.\le., and an interestmg receiver tl'St was recently carried out on the latter band at 2ZV. On signals from 201) a l-v- 1 proved to be most satisfactory, being 3 to 4 " S " strengths better than either an O-v- 1 o r a resonant lines model. 2ZV reports good conditions on 28 Mc. during October. The followi11g arc active: G2PF. SPF, t!RO, 2CIX. 2DDD. a nd 2DVO. 2BBB, who is in Egypt, hopes soon lo be on wit h an SU call.

T1111bridge Wells a11d 1·011bridge.-C{30B is tesung an ESW20 on 7 and 14 '.\le., and is pleased with the valve. 2UJ i ~ obtaining good results from his T 20 PA on S6 :IIc., and lms at last managed to work 2AO in Eastbourne on C.W., getting a report of S6. All reports on 56 '.\{c. transmissions will be acknowledged. Also active : G5KV, 50Q, SNO, 2AKQ. 2CUS, 2CUX and 2DIC.

IV/litslab/e.-Congratulations to 2C'.\11 on pa:;sing his )lorsc test, for which 2B]:ll is also in the running. GSCI, the T.R.. st:i.tc~ that he is discontinuing the local m eetings due to lack of support. (Tltis seem s most unfortunate. The subscription to the \V.R.A. is nil, thanks to the generosity of 5CT, who pays all cx-pcnses out of his own pocket, and, moreover, use<.! to provide supper after each mee ting.- D.R.)

DIST RICT 17 ( M id- East). Uu~l<m.-.\11 licensed members in Boston have

enrolled in the C.W.R. Congratulations tlu,, month go to BHS3 154, who has just. received 111:. H .B.E. certifica te. This appears lo be the tif!>t to be awarded to a BRS in Distric t 17. SBQ hai. now complett..'ll hb rebuild and is well satisfied with the rl'sn lLs, a new comrnunications receiver 1s colllu111plated . 21JTU a lso has transmitter on test. 6G 11 worked a few stations in the V l\:/ ZL conte~t. Regular mectm!(s are ht'ld in Boston on Thuooar e,·e11111gs and all are welcome. .\pply to 6GI [ for details of venue. etc.

Brii:g.-GS.\ I ' is fully :t\"t 1ve on 3.S, 7, and 14 :llc. The t'rl'Ction of a 50 fee l high laUice mast and a special 14 :llc. aerial ha.~ worked wonders.

Lwrolll .- G5Xli has ju,t completed a brick shack hut is having di1l1culLy with power wires which run across b is ganlun. 2CFT has applied for lus full licence. We an~ ~orry lo lose an active mcmht>r in 2C)L:\" who h,1, now left Lincoln. 5XL is completmg a new transn11ltcr and hopes to be active on the District 17 »chcdulc:..

.\fabltllzorpc and 5111/011 . .\II s tat1011s are known to be actl\·e although no report is yet to hand. 5BD ha<; rccei,·ed S6 )k »ignab from SGS 111

310

Crimsby. 5BD, 5C\"1

5LJ. arc worldng together regularly on 56 '-le.

(;rimsb1• A rc11. The winter schedules ha,·c ~ommenccd and most s tations arc taking part. 213XC is awaiting his full call and 'everal n<:wcomers arc applying for membership to R.S.G.13. :lleetings continue to take place on Tuesday t:\·cn-111gs and the winter programme is now in operation.

.\ District meeting was held at the Queen's Hotel, Lincoln. on Sunclay, October 30. Twenty-six members attenckd a nd helped to make it a g reat :mcccss. The D. H. wishes to thank all those who assisted in the transport arrangements, and rilso .5X L who was respon~ible for the exceli l'llt catcrmg a rrangements.

DISTRICT 18 ( East Yorkshire) Scarborouglr.- l t 1s a pleasure l O rt>cord that

:llr. Cooper (6CP), who is making exct>llent recowry with his broken thigh, expects to leave hospita l in the near future.

G2CP recently re turned from training afloat w ith the JLK.W.A .R., SKU was a lso warned to be in readiness. He i ~ now testing ' phone 011 7 155 and 14,3 10 kc. , and would apprt>ciate reports. l le is using QRP battcry-<lrinm 6L6 rig. 5:11\' is at present constructing a new exciter unit to drive his present PA 01\ 28 )le., and intends to e rect a WS] K aerial in the false roof. 6TG is active or 28 and 5<1 :1£c. 'phone and C.\\'., a nd busy with R.E.S. groups. He finds trus work \"C'ry interesting. Also lis tening on 56 )le. with Super Skyrider, but unable to lwar n1\y s ignals yet. He would appreciate hints for improving VHF performance. All suggestions acknowledged. Congratulatio11s to 2BGO upon his " )latching up." We sincerely wish !nm all happiness and luck. Has commenced a re-build to celebrate the occasion a nd hopes to be active soon. 2AHX recently joined R.S.G.13., but is well known locally, ha,;ng held A.A. permit three years-intends to apply for full ticket ~hortly.

A suggcst inn has been made to institute a local "rag chew aucl news " sc.hedulo on Friday ovening:;. Views wi ll be welcomed.

The T.R. regrets tlw absence of notes for the past three months, but this has been partly due to business and absence from town for training. ] le hopes that his successor will have better luck in obtaining notes from members.

8ridli11gto11.-G5\'0 acti\·e on 1-1 :llc. had D-101.C staying with h1111 recently. G600 has enti re ly !<crapped his old transmitters and is now rebui lding with AC·l Pen Tritet-'.J7 Doubler and T6 1D as P.:\. pending the purchase of a T55 as Jinn!. He ha~ hnd a visit from ;~ very old-timer. G2\'C. G6U J, ac tive on 14 Mc .. had ,·is its from G:lD\\' a nd G2\ 'C. G:JDW b interested in 56 "le. a nd wishes to ha,·e co-operation from others as well a.., G600 on this band.

Hu/1.-.\l the la~t monl11ly meetin!( a genera l talk took place on conditions. Those present decided to make notes of stations heard in October a nd to pool thei r reports in order to obtain a resume of conditions on nll hands at \'arious times.

Stations active include G5~1K . who is making some good contnc ts with an unusual aerial; 51-lA, who is putting out a good C.C. signal on 56 :llc. .111d would appreciate reports; and 31'1., 2QO, 2K:ll, :\Dl, SL'.I. . 605 and Gu\·.

The next 11 ull meeting will be held on Wednesday, :s'o,·em ber :10. at the Broadway Hotel.

I HE T. e.- R. BCl.LETJS, :'\o,·cmhcr 1938.

DISTRICT 19 (Nor t h-Easte rn ) I t is proposed by t :S\\'Z that if sufficit·nt support

ran be obta ined, a !\o. 19 Dbtnct " Hamfest" be hl·ld m ei ther Sunderland or South Sbiehls, and thal a ll !'xpenses be shared (including ir.wellini: expeni;cs) ~<> that e,·erybody attending will pay the same. \\'ill all members w1lhng to support this please drop a card to GS\YZ. ·· High L>ock Hou~c." \\'est llolborn. South Shields. The U.R. " ;shcs to point 1111t that South Shields poss1•ssrs the only oOkial T . I<. in ~o. 19 District. \\'ill other town~ with h\'I' or m11 rc members please send 111 the form l'lldOscct in las t month 's issue "" soon a'> poss ible ?

So11tli Shields.-G5\\"Z is again active on 3.5 i\lc. ;>SB has completed new rk 6L6-T20 and tc~ts on 7 :llc. promise well. 6\"G 1s rcbuild111g. SlF ha-. r<:ce1ved 25-watt pcrnut. $\'\' is reb111lding J'J\ and anticipates 25 wa lls. SJO is busy "ith aerial problems at new C}H:\. 8.\0 has new l>uperhel rt•Lci,·er. HXO, SK lo( and STl; a re alw known to Ix: .1c tive.

S1111de1•/1111d.-G6TH is operating 1.7 ;\le. phone a 11d CW. HC \ " is working 7 :\le. phone, while 611 V and 5HC arc acti, ·e on I~ ~le . 31\" and S.\ R arc al-.o acn,·c.

Stockto11-011-Tees. C2FO is building unit to double from 7 :llc. to 56 :llc. GZT has new receiver. 50l' is acti\'e on 28 :llc. and 1s concerned about ,<:ry s trong ground wa,·e. 2CZO has at last got h1~ lrans1111tter perfonning >.a tisfactonly. 2J3~Z ;, now 3llG. Congrats , 0.:11. ! Other act1vo s tations arc .5XT, 60 1~ . 8CL, 8 1'5, 801-1 .

Northern Ireland The quarterly District meeting which was held

in J3elfas t on September 30 was very well aUcnded. After tea GISTS O!)"ncd a chscussion on 56 :lle. portable work with an account of the G lSTSPG\\'6AAP contac t earlier in the summer. STS, who has s ince transf,•rrcd his QH.A t emporarily to Cambridge. says that. before lctwing, h e was getting out quite well on 28 i\lc. C.\\'. and phone, using the T 20 PA as a frt'qucncy doubler at \•cry low t·ftic icnc,·. 5TK is now WAC on 10 watts with :l hand generator, and reports his 58tb country on l .J )le. t:sing a 66-ft. Windom. 2KH. continues active, and has rai~ed 11P2 for lhe hr.,t time on l ·I :lle. 6TK has found 28 )le. \"Cry poor reccnlly as compared with the same time last year. l lo is a lso acli\'C on 3.5 :llc. C. \\'. a nd phone. ;1ncl hopes to have a n SJK bt'<\111 e rected shortly. 5l.i0 is lc•aving C I for G. a nd, like STS. has the good wishes of all !\.I. members. SPA is s till "wiggling the dhrr" a nd ,,·orkin!( an odd \V on phone. 1 le is rd>uilcling for 28 :llc. Several others report active, hut ha,·e nothing of mterest to comm unicate.

Particulars of the next Di~trict meeting will appear in the Deccmbt•r issue. The date 1s Friday, J anuary 1a. but some· Ulste r fo lk say that is lucky!

Transmitting mt•mlx•rs a rc· asked to keep the local records up to da t e by :.ending to the D.R. brfcirc ::'\ovcmber 30 particulars of tht'ir prC'Sent :

( I ) Crystal freq uencics. (2) Licensed bandll and power, stating whether

for C. \\'. only or for phone. (:I) Application:-. out ,tandmg but not yet granted,

for o ther band~ or incr,•a,ed power. (.J ) Full particulars of a ny frequl'ncy meters

in 11,c.

THE T. 6- U. BULLETJS, );o,·ember 1938.

Scotland "A " Dislrut.-Thc 1938 R.S.G.B. Films were

<li~playl'<l al the October meeting, and a large audience enjoyed them despite the hitches caused by the -.talc of the films. The D.O. would apprt-ciatc any offer.. to gi,·c l>hort lectures. Sc\'cral ~lursc lnstrnctor.; .ire also urgently required. H is likely that regular tran~m1ssions on 56 ~le. will commence in the district i.oon, G)l6)1S has already started, whilst other stations arc making preparations for activity. G:\16:\IS and 6ZV will appreciate hcarini.: from members in a position to receive 56 :\Le. ~ignals, stalini.: whether able to recei,·e both C.W. and tclcpho11y or telephony only.

.. IJ" .Disl1icl.-Sincc these notes last appeared the .\bcrdccn members ha\'e enjoyed two of the most inlt-rcslin!{ meetings of the season. On September 30 E. C. lnl{ram (G:\161Z) ~a"e a talk on ".\mateur Hndio 111 the l'nsl." 61 Z is an old-timer, and no one in the dbtrict i!, more capable of talking on that .. ubjcct. J lis remarks aboul the old day:. on 90 mrlres and the troubles experienced with apparatus, were a revelation to most of the 15 members present. It is hope(! that other members will follow 61/,'s exnmplc by gh·ing talks. On October 14 a dcbatll took pince on the power question. The motion was " That this Society considers that high power is neccsi.ary for modem amateur e)(perimcnts." A. Fowler (Gill SS\') supported the motion . :rncl D. Simpson (C:\IG\'O) opposed. Two hours of good constructi,·c argument was hacl by all pre; cnt, and when the vole was taken there was a M>lid majority agamsl the motion. The motion was a d11licult one to "upport. as neither SS\' or any other member in t.hc district can speak with expenence on the !ugh-power question.

General acth·ity has been very mild of late, and no reports of ouhtanding mterest ha,·e been received. Four member:; await their .\ .. \ . C:."\lls. The vi~it to the B.B.C. station at Burghead was !{really enjoyed.

" C " District .-1.a-.t month's notes were mi..sed lx•cause the\· did not reach Scottish Records Office in tinw owing to delay in the mail. At the district meeting held on September 20, cliscussion centred a round the Scottish Convention and several suggestions were made for the next. One is t hat a more central venue, such as Perth. be chosen . Mr. Walls' i:ood work at Cair9 was deeply appreciated.

'' /) " Disfl'ict.- Thc.: meetings continue to be well s11 ppnrt('cl. /\II licensed members arc active, but with nil to report.

" E" DistYirl.-The usual monthly meeting took place on October 19, when tbc 1938 R.S.G.B. fi lms were displayl.'d. Thanks arc again due to :\fr. A. Fnirbairn (l3HS2474), wbo was responsible for thl'ir screening. The morse class continues its weckly meetings and considerable progress falls to be recorded. Thl• next District meeting takes place on Xovcmbcr 23 at 7.30 p.m. at Fleury )[cog's, .is. ~.:wmarkct Street, Ayr, when lli. Douglas Lamb (G:\12UU) ";u deliver a lecture on Aerials. Indicative of the enthusiasm of the District is the fact thnt at t he October meeting two of the members attending came from QRA's eighty miles apart. Reports arc to hand from G)l2LU and BRSl295. The latter reports that on October 16 he had the unusual experience;, of hearing ~ignals on nil amateur bands between S and IGO metr.:~.

311

" F" District.-:\kcuni,:-. art• ht•mi: \\ell supported. It was decided to hotel fortnightly meetings, but it was Inter discovered that till' would be incon,·enient to se,·eral mt•mhcr-.. "° thc idea has been dropped for thl' pre-cnt lht• d.lle of meetini< is to be altered in thl' nl.'ar futurl'. from the first Sunday to either the ,econd or t hml.

" G " Districl.-~lcclmg-. an• lx•mg \\ell attended· and a " Question Bee " i~ holclmg great interest· Congratulations to i\lr .. \ndt•r-im (2(' ~C) on obtainin!{ full call G:\13TD. Th<' mast" at G:'l l6HG suffered damage during llH! rccl'nt gall''· A fine job was carried out in replacing n. 10-ft. section at ll.1c top of an 80-ft. mast. \\'ill llll'l\llwr-. pll'a'c report on acti,•ilics to t he D.0 .

"H" Dislricl.- \\'ith the ad\'l·nt of winter. most stations are acti,·c, and SC\'l'ral m•w calls appear on the list. 2CXY is now C::\1:11.0. 2DIL- GM3SR. 2C\\'G-G:'ll3):H and BHS2n9:1 G~l~IZ'D. Further new calls are expected in llw near future. \\'c ha\'C pleasure in welcoming :'llr .. \rthur Dyer, B.E.l<.S. 379. to the district, and to \1 hom wt· ha ,.c to thank for gh·ing a \'cry interestmi: talk on H .. \ .F. transmillers at a recent meeting. \\'c alw thank G:\13Z'H, who. at a later mt·l'linl{ g;wc a talk on LF Class 13 :'llodulation :wrnmpaml'd hy diagrams. Further talks or lectures wouhl he nnu:h appreciated, and any member willing io oblige should nolify the D.O.

The District transmitter will ha,·c reached completion by the limo these nott''l appear in print, the call being G:\13DR. Co·o1wration. conci~c and pertinent reports will be appr('c1alt'd, QI<,\, 3a, Bank Street, J(irkcaldy .

. \rrangements for the l>ist net's ,\nnual Dinner in January, 1939, arc now m hand, but fuller information will appear m tht· n<''(I issue. lt is hoped that the );.F.U. film-. will ht· shown in a few week's time, but member-. will lx· not1fl~'C.l individually in due cou~c C)IN:'ll<) 1, 110\\ \\ •• \C, \\'BE.

British Ca lls Heard Eric W. Trebilcock (TJ£US 195). Pou•ell Creek,

;\'orlh Australia. Septem/Ju 15-0rtol1cr 12. 1938. 7 Mc.-CW: g2nj. Sfc. 14 ) le. 'Phone: g2hk,

3ln, 5jo, Gjl. Gtz. 14 l\tc.-CW: g2cg. 2fi, 2fz, 2gk, 2hw, 2io, 2km, 2kq. Zin. 21111, 2sy, 2xu, 3ad, 3ap, 3bu, 3cw, 3cy, 3db, 3fz, 3hh. 3ih, 3iq, 3jr, 3pg, 3pw, 5a n. 5dy, 5hh, 5ms, Smy, Snd, Sns, Spc, Spr. Spy, 5rv, 5sg. 511g, 5vb, 5vu, 5wp, Syu, Szt, 6bq, Gell, Gcj, 6cw, (idl, (ig t, Hlb, Gmk. 6nb, 6pr, 6qm, 6ti, Gui, Gvx, 6wb, (iwr, 6wy, Gxl, Sab, Scz, Sgd, Sgo, Sii, Sip, Sit, Siw, Sja. Sjb, Sjv, Smy, Snv, Ssy, Spo, Sug, Sny, gm2jf, 2kp. 3ba. Srh, 6bm, 6hz, Gis, 6rv, Sfr, Shp, Skq. gw3nx, 51\-, Suh.

Strays )!r. "'. D. Oliphant, 2FI.Q, " J aracldo," Burkitt

Road, Woodbridge, Suffolk. Wlll be pleased to cooperate \\;th any ' phone ,;tation de~1ring li~tening schedules.

• • • We a rc informed bv C2SU that )lr. D. C. Derry,

GSPQ, sailed for India on Octolwr 2.'i. H e hopes to contact British amatl.'ur,, .1s ~oon "" his station is built.

31 2 THE T. cS- R. BULLETIN, Xovember 1938.

The West at Weston The diUicultic~ which prt.'Cl'(ll'tl the \Ve,..t of

England and South \\"aJes Conventioncllc held at \\'e!>ton-super-'.\lare on Sundar. October 9, were such that al one lime it i;ec11100 likely lhal the meeting would have to be cancelled. The arrangements locally were in charge of G6LQ, who, being a nwmht•r of the R.K.\\".A.H .. was, wilh many other-.. call<'d up during the crbis. In adclilion, owing lo ' tructura l alterations at the original meetrng place a fresh venue had to be found. Fortunatt•lr. I luntlcy's Beach Holcl wa~ able to provide sullablc accommodation at somewhat short nolice : the cuisine and a rrangement., turning out lo he excellent .

,\ part\· of 5-1 ~t down to dinner in a room singu larly· a ppropriate to the occasion. From its windows coulcl be had a fine view of the Bris tol Cha 11n1•l, with BrC'an Down on the one hand and the isl:wds of Steep Hohn and .Fial I lo lm on the other. Hctwccn these points the late Senator l\ la rconi conduct ed many of his t•a rly wireless experiments.

The gathering, drawn from far and near, included the J) . l<.'s o f Districts 5, Gaud JO a nd seven or more T .H.'s. In addition , we were g lad to have with us our Secretary, GGCL, and Squadron Leader St. J ohn, Chief Instructor of the R .. \ .F. Ci, ·il \\'ircle:.s Rcscrve. .\lr. \". )I. De:.mond, G5Y.\I, D.R. of District 3. who had iuteud1.'(( tlying from B1rmmgham, was prevented from attending through the rough weat her which pre,·a1loo. One party, however, did fly o,·er in an air bner from South \\'ales and we· bclie, ·e enjoyed the ex-pcrience; another from \\'ales and :'llonmouthshire travelled by s teamer.

The afternoon proceedings commcnc1.·d with the chairman, ) lr. ] . ~. \\'alkcr, G5JG. officia lly welcoming tht' members and cxprc:;!!ing lhe o rganisers' apprC'cia lion of their co-operation in making

the meeting "° succc,sful. .\lr . .-\ustin Forsyth, GGFO. and .\lr. \\'alter s,·dcnham, G5SY, follow1.'d and poin lt..'CI out the adv;in tages and disach·anlagcs possessed by \\'eston as a Ct'nlrc for such meeting:.. On the whole. lhc choice appeared to be a popular one, and it b ltopl'<I to hold ei ther a P.D . .\l. or Con,·entioncltc t]wrc n<'xl year.

:'\ext followed lhc pn'scntation of the G5FS .\femorial Challenge Trophy lo :\lr. L. E. Crabbe, GG\"F. in recognition of bis outstanding work on the " ullra-,horh." .\lr. Clarricoats in making the pre;,cntat1on. paid tribute to the service,, rendered in many w:ty,, to lhe Society by the late .\lr. \\' .. \ . ,\ndrt'\\S (G5 FS), and noted with pleasure the rca'>C">11 for the award of the Trophy lo (;(i\"F.

"Clarry" then prodm't•d his famous little black book and got down to " brass tacks." Despite a severe cold from \\'hich he was suJiering, and which, incidenta lly, had considerably hampered the scope of his visit, he held t he in terest of his audience in his usua l inimita ble fashion while dealing with th1· many a nd various matte rs appertaining to amateur radio.

Sqdn.-Ldr. SL John look the opportunity to inform the memb..•r, of the progress being made by the C. \\". I< . It was apparent tbat many present were g reatly in tcrc~ted I learty thanks were accorded to both ~pcaker,...

A bullet tea w:ts follO\\l'(I by a display of society films. which "ere \'t'C\" fme, both from a t echnical as well as an ent<.'r talnmcnt point of view. Some members had to lean· early lo Hr back to South \\'ales- undoubtt'(lly a fascinating experience on such a fine, moonlight nighl. The other.; formed into parties to vi,it local amateur s tations before frnally wending their way homeward after what, all were agreed, was a very pleasant day.

THE WEST AT WESTON Srotrtf from ri11h t to frft : C6AC. 6R.B, SQA, SLM (Mayor of Taunto n) , 6FO. StlU. 6CL

anti So. Ltfr . H. W. St. John . R .A.F.

THE T. 0- R. BULLET!.\", :\o,•cmbcr 1938. 3 13

BRITISH EMPIRE NOTES AND NEWS

Australia (Western) B,· Y1'6\\'Z.

COXDITIOXS for the most part haw been poor >incc our last notes were \\Tillcn. 1-1 .\le. has suffered particularly and DX has been

'very hard to obtain. The b.-ind wa~ dead on September 20, and during the worst period e\·en V K signals were inaudible.

The 28 )le. band seems to be picking up a nd on October 15 signals were heard during mid·aflcrnoon for t he fi rst time since last summer, hut strangely enough they were from VJ<3 only. l\lornings sti ll remain best periods for 28 ;lfo. work hen~. \I J\6LW, GAF aucl Gl\l\V opera te on t his band fro m l ime to t ime.

VK/ ZL Contest scores arc not yet known, but VK6AF put in much time on the Senior Evcnl and ran up a total of 16,000. \ 'J\6)1\\', 6LJ, 6Fl. and GSA were also known to be competing.

Xcw licensees include VKGFK, 6EL and GLR (ex-3TQ and ex-GLR of many yea~ ago). all of whom arc active on 7 ~!c.. which rem::uns the popular " local " band.

VK6LJ's rotary beam, mentioned last month, is now working satisfactorily after a preliminary ~pasm of end-lire operation instead of, a~ intended, broadside.

The. VJ\6 DX Con test proposed hy the T.D.S. Committee of W.I.A. will take place on :November 19·20 nod :November 26-27, commencing at JOOO G.l\1.T. on Saturdays and finishing at the same hour on Sundays. It is hoped that olher parts of lhe Empire will support this e\·ent.

Eire Bv £190

.\t :L mecling of 1. R~T.S. held reccnlly 111 jury·s llotcl, Dublin, the X.F.D. 1.7 )le. replica was prescnlcd lo E l6F and the station 1~rsonnel. \\'e hear that, encouraged by this ~ucct•s.,, E 16F has a ln·ad)• on test new por ta hie gt•ar. I la ,·mg taken it far 111to the wilds for a real try-out, however, the power output proved disappointing. It was then found that the 6-\•olt car battery 111 11~ did not hnc up very well with the generator. which had a 12-volt mput ! Here in the \\'est we th111k that things happen much more satisfactorily when the figures are transposed. Anyhow it is a fact thal 6F is installmg a b.-ittery charger !

1:11<52032 reports from Bray. lie 1s hard at work on code, and hopes soon to qualify for Cull licence.

Thu usual aelidty continues, but there 1s nothing of special in lcrest to report.

Malaya and Borneo By VS2AG.

The writer for two reasons offers no apologies for the lack of notes since YSIAA went on leave .

•

First, heavy official duties and flying training have not permitted much personal activity at lhe transmitter; secondly. and more important, only one report has been rccch·cd, and only one acknowlcdgment of regular dbtribution of QSL cards. Jlowc'\·er, and unfortunatch-, thc.,e conditions do not appear to apply exclusively to )lalaya ! VS2AL using only 9 watts to an RK25 on 1-1 :\le .. has been getting '\'Cry good DX, using at choice one of two half-wave doublets. l{cstrictcd operating time permits only \VG, VK's, j 's a nd VU contacts as a genera l rule, but a n a verage report of 569 Irom WG is very good.

VS2AE act ive in his new location is get.ting out well. 2A K has gone on leave to E ngland, and judging by the pile of QSL cards which arrive by each mai l, he was \'Cry busy before he left us.

YS2AS 1s acll\'C, but volunteer wireless duties take up most of his time and energy. 2AR is also active, ancl although skip renders him inaudible to 2AG, stations ha\'c been heard ca!Ling him. 2AG now in Kuala Lumpur, is using 6L6's to a W.E. 2-1 2B final, which gets the same reports as the old rig. Propagation ob:.er\'ations have been fairly continuous since 193,1, and certain facts arc beginning vaguely to appear from out of the welter of reports. The i,ystcmatic analysis of results often iakcs twice as long as the actual QSO.

VS IAA is c·xpcctcd back next mont h, and being fresh from leave, he may be able to wring reports from '.:\la layan members!

M alta By ZBIE

After a lono.: 'JlCll of silence, broken only by an oceasionnl European ,,ignal, the 28 )le. band opened up for JXttchy periods during October. and \\ .. s came Ill both on C.\\'. ancl phone at S7. )lamly because of thc:.,e relatively few good periods the 28 ~le. band has bct•n ~adly neglected in ZB J.

All stations arc active. ZB I E is conducting a series of experiments with various crystal o:.cillators and frequency douhlcr~. while I H is rebuilding for telcphonr in the r.tck and panel style. l j i~ back from his holiday 111 (; and active on l.J )le. I L has been trying out his new modulator with excellent results and 1s now wailing for a new " mike." IR is very busy on 1-1 )le.; and IS and I W are both building their transmitters, while l X. b over-hauling for an im:rca'e of efficiency._ .

\ \'ith regard to the query by ;,6 '.:\fc. experimenters in G, the "·riter wi~hcs to state that after enquiries made al the last general meeting 1t was found that. at present. no member is prepared to rake part in -.clwcl111l>cl listcninit or transmitting on this band owin~ to other activities in hand.

New Z ealand Bv ZL3AZ

The return to warmer weather has brought an improvement in condit ions on the higher frcquen· cies. Another welcome p iece of news is t he fact 1lmt several amateurs are taking a n in te rest in 5H J\Ic. A 'Wellington listener, Mr . .P. Morrison , has heard W6£NC and V l\2NO on t his band . a lthough a QSO between ZL anc.l VK has not \'Ct been established. · The Auckland Group continue to lead in the matter of DX on 14 '.\le. H.umoun. have it that ZLl'.\IR has at last worked the 40 zones. This is certainly very fine work, and confirmat:on is awaited. ZLlGX bas not been as active as in till' past but recent QSO's have included VR6A Y, 171\A and V03X, all hard contacts for us in ZL.

Judging by the n umber of stations on the air in the VK-ZJ~ Con test it was a comp lete success. Conditions were fairly good, a nd although t he writer am:tssed 30,000 points, by the w;iy, some of the Is! and 2nd district stations were knocking them oil, their scores should be around 250.000 ! One South African onh· was heard, this was ZS2F. l le was really the' only outstanding DX station Iogi:ed. AJI the usual European countric;; were audible, the rarest probably being ESI E .

Dunedin seems to be a good spot for DX, as ZlADQ reports hearing among others, EL2R and ZC<lt-:X. He operates on 28 r. lc. quite frequently so ~tations desi rous of a contact with this countrY 011 28 'i\le. should keep a look out for him. ·

J\ 11 even t of local interest was lho depar ture of ZL:IJ U for Winnipeg, Canada. lie will be in that city for at least 12 months, and hopes to bo on the air with a VE call before long. The writer has be1•n keeping in touch with him through VE4RO and many very enjoyable QSO's have rrsuHcd.

South Africa D1l'lsio11 6.- The Jubilee of \\"1rcless was cele

brated in Johannesburg on Aui::u;,l 25 by an exhibiuon staged in t he Physic,; Laboratory of the Witwatersrand l,;ni,·ersily, hy the South African I n~litute of Electrical Eni:i11cers in conjunction with the University. The ohjcct of the exhibition was to show the dc,·clopmcnt of wireless from t he very beginning. An attempt was made at tbe exhibition to reproduce as nearly as possible the apparatus used by Hertz fifty years ago when establishing the existence of wireless waves.

The many interesting features dbpla}'ed included a portable transmitting and receiving set loaned by the t:nion Defence Department, an aeroplane set combining transmitter and receh·cr, with direction finding facilities, dsual and aural, lent by South African Airways, and an exhibit by the South African Broadcasting Corporation, including an early type of military tranM11itkr and speech amplifier.

l t is perhaps intere,.ling to mention that South J\frica, especially the Tran;,v:ial, is to-day leading the world in the lightning investigations which arc being conducted in U1e Bernard Price L'lboratory of this institution.

The Postmaster-General's new regulations arc expected soon, and it is rumoured that the use of 100 watts has been granted. \\'c hope to substantiate these premature remarks with more concrete information, in the next issue of lhc 11t:r.LETIK.

TI/£ T. b R. si·LLE1 IS, .:>;o,·cmbcr 193S.

The followmg ~tations report acth·c : ZS6B~ o.n l.J348 kc. 1s looking for Empire contacts, 6Bf 1s work111i: on I .JOI-I kc. with his new" stream-lined " transm1llcr, GD:ll fi nds plenly of DX on 14 )~c .. GE)f has ;\ new R:.\ (£69, 6SC is on 28 J\[c. wi t h 'pho1ll' using a fu ll wave Zepp, Gl.>7. pi.cased with his ini t ia l B.E.R. U. Contest resul ts 1s now on 28552 l<t'.

West Africa B,· ZD211.

ZS6DZ.

S1ort1 l.e.me.-ZD IGT, the onlr licen~cd amat~ur in th1' lolonv, is off the air at the moment owing to a tr.in~forn1er burn out.

Sigc1111.- ZD2G has transferred hi~ aerial s):s~cm to a new QRA. ZD211 notes varying cond1tio1~s, with l'rmtic spasms of DX. Terrific QRM. is caused by a commercial station on 14 Mc. s1g11111g Il3S (HST591). BERS-I.JO is on leave. •

Gold Coast.- P ressurc of work bas caused ZD4A 11 to be rather inactive o f late, but a Sunday schedule on 7 :IIc. with ZD2H (S9 both ways) promise~ a reliable communication channel in l.pitc of the high nobe level.

" T . & R; Bulle tin." ADVERTISEMENT RATES.

Per lnsuUon. Per lnsudoa. Putt Polle • • £6 U 0 Hnlf Paste .. .CJ 0 0 Quorter Pajle I 10 0 EIQbtb Pngc 0 15 0

Seriu Dite0unts-5~' for 0 or 10~~ for 12 tonstcuti•e Insertions. Full·page t ype area 11· x 5t•. Adverlisemeot.s specified !or Co•1rt 11nd F11lint J.{ loll" Po1itlonr are not subject to series di<e<>uou. Tbe T. & R. Du LLETI!< b published on tbo 16tb ol each mootb. Orders Copy And Blocks should reach us by the 251b ol w eb a:onth lor the following month'• iuuc. All applications !or •pace or 1pcclmco copln should, pl•ue, he scot to Advertisement Manaccr,

PARR'S ADVERTISING LTD., Cr aven House. KJDQswny , W.C..l.

"'\ T .upi.-,: H olhorn 2 40 4 . r ·~~~~__::..,_~~~~~~~~~

INDEX TO DISPLAYED ADVERTISEMENTS

A.C.S . Radio ... iv Automatic Coil Winder & Electrical Equip· .

mcnt Co .• Ltd. ... ... ... ... Cover ai Brltl1h Mecha nial Productions, Ltd. (Cllx)cove r ii Brookes Me:uurini: T ools Brown, S. G., Ltd . ... Candler System Co. Central Radio & T elevision. Ltd. Elcctradix Radios ..•

308 v v

Evrlxono Radio & T e levision, Co., Ltd . GSNI (Blrmln1ham). Ltd. (Radloma rt) GW3GL

316 196

vl ill

308 Hla h V1>euum Valve Co ... . " Hl1 Ma.ster's Voice•• .. . Oliver Bell Control, Ltd. (Varley) Pitman. Sir Isaac & Sons Premier Supply Stores Quaru Cry1tal Co., Ltd. (Q.C.C,) Radio Construction Service Re ad, N . E . ... Short-Wave Radio •. . Stratton & Co , Ltd. (Eddystone) Televis ion and Short-Wave World Webb'• Radio

Front Cover 179 308 196 295

196, 308 308

307, 3 16 316 vii

Back Covor 267

Weatin1hou1c Brake & Signal Co., Ltd. vl

Win11rove & Ro1ers Woden Transformer C.o .

iv 196

7 Ii T: I ,~ N Ul '/././:I/\.. '"'·ember Hl~\$.

Q RA Section Ry II . I\. \f. \\

0

11\ Tr (Gil\\'\··

,\'h<'n ~ending in new, or changes of QR:\, members are requested to print their nam~ and addresses 111 block letters, ns frequently signatures and namcli of street s are illegible. This necessitate~ r<'printing the corrtctcd ad1ln•ss in the next 1i,~ue of the Bt.:1-11-:TJ!\.

New QRA 's I l."1J. - l>tti\IOf Tun''·" No.k\1r\\, .. \ll>w·tt R'li-l.CI, Sh,v. c, \l:!AP. F ' "·"'""· \\ kKr.uho (H:ou'-"'· \\'ick. r.1t thnt:::. ...

Scotland. <;:!1rr. F. J !'t·~"· ~. Uliuro t.10\t•, Camhrldi.:1·. <.:!1\1...-f'. :\ E-"-'''• "111c \\ uod \\'ardc11,," Hi:!. \hwf .. tOnt·

Road, \\'agmor<-. l~a111h.1111, l\rnt c ,:_!I. r. E. \\'Au:CK, ~. HarbC,iril J{o;ul. ~lwth1 hi , :-., YorJ.. .. t ~:!OU. S. \\' 11 1Tc, 1:1, Kt•nilworth Avc·nw·, Dnby. C:.!l 'S.- ( ( ' ~1'Htl l\11 H, a .. o,\ , I 011don 1{11.l(I, ~t)rlh l h('all1,

Surn ,. I ,:!\'Z.- H. \\ lht,\. IHI. l..irnp ... ru·hl l(h;l41, ~.uuJ,-r"l«•tul, Surrer. 1;:!FA.· II lla•K"• llA\\, Dorr., Shrlt1Plcl, Yorks. I .:wn /f\·\'E:• llJ ), 1\ , l.i osAwr><.'1 ~ " ' s," ll ollybum," l·:ym;baan

<.:lo..:..·. Evu~h:i 1 u A\'t'llll(", li lt ln 11r•, $(01tha11 ~1>ron, I font~. t,:J J•\\'. c; \\'. R1 ... 11 '· !\'c.:wCO\\ll. Pppjngb.1m. Rutl:ind t.:u K <. ""'It"', ~•. k1rh\'illr l(o.1cl. ~hirl1•\', St>uthamptoo.

Ham ... t . :~ 1.c. It . t llA\IUHU '''· 1m. U.ikt•r Strp•t, llurh'>U nn rrf'nt,

S talls. c .:u.w. J H ~la'"'· :10. """ Ho.ltl. c:r.n·-. "'"'X. c i:t)l h:.· S JhtMLI ', r.c1, L,"( .. , ... Stn1'L Shdr1dd • ·:l='J .... J,uK"'O'· Thr Cott.1.:r (runkh1ll JIJIJ, t<m1 ... 1k,tom;h,

t\t"M l>uu1 .uttr. \'ot~ .. l~\l:JKh'.. \ t'11ArLI' · ;j, t\ni..:ht ... t lilTe :\\ t'llll<', lila.;J;V\\, \\'.:J,

S.--.>tl.uul. t,:l ='T. l( OLl\.lW. thlton ( . ra10..:•·. :'\orttnlJ4·rto11. YoiJ... ... 4.:JOC R J lh·,n,c •• ~1 Lu~ ... • .. K•""-tor}\ fhH-tha.m. lJ.1n• h~Lt:r <.JOI. R \\aL-o~. "ll:I • Fh~ht. ··I>" '"lll•ttlron, !\o :! \\'in,::.

E. ;<. \\' School, It .A F .. (r.1m-.ll, L111r,. c .aou. J. II l'AN:K1,, ~u. t;rrat..: lfou"'4..", f1r,t·u1, Shc1firltl. :,. c,ar.<\. \\._.f. PAGL. l 'i:!, , •• nnf"r J~o.1,t.S~·cknh:un, London, S.E.:!G. t,'.U'G~ ll. \\' fuu tr Hro&mptoo Ro..ul. \\'f"'t ,l,.hc.11, 114"4111r

Roth .. rharn, Yock" c.~tPL. R.\\' \\"At"Tl. •~I . U"°'\cl\\,I\' S"onh.uupton. c.:tQC. ( . JI ·~DLl:rr..: , •• c • .imbru.1:· 10, Pt>11lhun· 1<0.1J, \\ulf~1on.

~01" I .~QY • I' ~ (;1 LL, I I.I, M1<1 Hall It"'"· \rnolcl, urar Nottm~hana. t ,:CKH R. r. Ht.\\ .. o, .;:!, Orw-osh:m Ro.•cl, ...\bbc\0 \\·ood,

l .... ond1111, ~. E.:!. t ,)f3SA. T. <iw11.M:-O:\, \h\'ft• Frn re~. '.\lor.ly .. Jurc, $(,ot):'IHtl. <:asr. " · l .nt1Lac ll' •11.11 T, ~li ll Hoel Hou-e, l'haxted, l'><el. ( ,:JSX.- K. P. E.1 u ... !'o. J, Station \'it·\\._ Frru Hill. ~orth JZ;i,non.

°""on. «~:J.."')P.-J. \huu ~T. 17, l.ii1tol11 \\·tout, f.,.,·t-1bhulmf". \Ian·

1'hPSh.•r ( .asu. R. r\, :\J w11., "' "'rrofl ~." IJ,yworcll, Pet worth, $ 11$::_.ex. <::rrc:.- IL r. (oot•J N, ll:!, 1< 11 1u-... 1ra<I frt .. •4'('111, Cr',''JKlO'·

Sh<ltatld, IO. t,M!JTD \ . A~n• N-'o~. H°•. !'\h11\\httn1 Ro .. 1tl. Sc-lkirk, Su1tlJnd. C.3TF. T . 1;A11<, :~. \ \ 'rotte,1<•) 110.1<1. Tetl<'rlh~ll. Stalls, t;!JTJ. H . .i\ . T'A P~I If I.It, ;, Ord1.11cl ,\ \'Nlllr-. Fin chlr)'. Lo11dou,

:'\.:\. 4 ~:fl'I.\. H. H. \ \'ouo, :!:•. }\i·uwood .-\\•("11111•, l.A""igh, l.omt·~. t;:n·~t. E. ~!ALI'.'<. ... :!•~. J.i\•t·rpoul J(, ..,1d, \\',uringtori. Lan-.· .... (•:JTO. ·A. It. no!\ \I 0, ;;, .\~hi.cro\··· .\Vt'flUf'. \\

0

{'Jotl llnrtlfp()O). Co. D11rhn1n.

c~:tTQ. P. Axu1 Mio:oN, " \\'< .. ~l \'l1•\\'," C.1 hcf1111ia11 H• •.u.I, \\"est Hartl1·1>ool. C'o. J >11rh.un.

<.:. rs. - A . c. L. SI IUU IJ I u. .. Jl i~hrlrhl,'' Invt"rllt"'' Ro~d. LaandC'lti. I ... ~A.

I .:t rr. W , 1 .. Lu, I;, ~t1rl11111 l<u.ul. ll.1"·'· )la!ldlt·""· <t:JT \ f. H. ~. \\', TKIM, " lsn' roh," :?t~. !';irk •\\ ('ntle', fnv·rham·

on·tlu· 1 lill. Surrt'\'. ( .:J rx. Jou' Eon\. ;.:., 4 tfN·11h .. u1~ \\ c•nlh•. 1.ip'"'<m, l)h·nK•tnh. ,.,,.,, .... 1.;n?H I 1 \fA !litO,, :?• • ..-r.1"'"' l(rJJcl. '•rttoford, \hddlh ... , t,:cl: l.\. (. \ . \\'utTrH.t R, I:!, l't rrv StrtTt. Dudley. \\"on". t .:\t:JUll . c,. I'. :\hLL~M. ~. llt rriu tm.{c- (~:.rdrus. l!.dinhorJ.th. t .:1uv. Aun MT Lu ••. I:!. Sht r\\nod Ro.ul. Ughtwf'XMI, ~t,,J.., ..

(.l[I· r,. ru, ~tafi• f~:H 'Q. (;1 u . .\. TuuuTT ... ;o, \\orwhoh M03d, ~~phErd"

R<oid. 1.umlon. \\' I:!. c.:iuT. L. 1. LctOLM. ~II. l.O\\r'r 011.rnd Str•·tt, Bung3\', Suffolk. (~\l:it:U. A S. \ff'~ll or~ ·· :\1rl1t·," \\ r...,l l}.ark Ro:ul. ('up:u·,

f"i!•, '4:ootfand.

:ll5

<~:n I>. H. \ . J11 1 r11. ·• IJu J..rnr,.J .... " \\·orrm l<li..ul, Shrnrwld, ,... .... , \ .

c;.jH/ S. J nu'" M. RthL\·ford )t:a.1.0 nf.M l>.uhni:t•~n. \ 'hr&. ... r;:1LR L (~. lh , .,,,, u .. i t:J. Tm"" v,,.w, :'hirlr\", Crrwdon.

Surn ,._ c-;:..Q<. \I. JIOIL.1!\~ll l \U , 10:.?H, 1'1·r .. hon Moad, Sdh· C>~'k·

U1rno111!ham. :..tti G:. to((' R C. lHa,r, HI, Ehn 1;ro,r. llhtl)\', \\arr.ii. (h,., c;:,Sf. ~ \ . 1 u" \tUh. R..idtopolt• Hto ,,, ~1211rnu Rend, ~h11IM· .

Sh111h:unptun t-;.:,01> <~. D. S 1 ;s1n~R,,c>nh1 17, f~o~·h1·rry ,\,11111t·, t~:l'''''"._J,

1'111c\ L\·1111. ~orrolk. c;.;xu. -n~:n. f CHR•'-t•"'· ..... \\'c-.c•lku. IHM· u. hin..:-1ou Llw,. t"";:1X\ I I) ,, .... "St. ~IJ~11u,," r ;i ... tt n 1{0;;,.t. lf.n-ant. H:.nt .... t;oHP If (;. (, (11,._,.,. 1- M," flf':t'U'' Jlou""f"," \\ rdiounk Ro.lit,

t-7.1n1ham. Surrl \'. l;t1HI. !t•x-ST~ll, SllOHI.), I' S~t. J. I' lhu , ll \ .F. l ~·t,,, h

11\fnl. Blafk I .ion Fidel .... t,i1Jin1eh.un, }\,1u. r;.oH\" U. Jf r u • ,., 9•, ln1lt:tm RoJtl, Huh,,·11. !\nui11i:,h:1111 1;r.o;;. ). \\ . f ,11a .. 11.;, l'Mkfirld Ori\,, Hull, \'urk' c;~;\\'11, \\·. 1;~1\tHALDl~:-10~. io. &let .Stn'f't. IU,1rkhur11 1 f..Jlif,, (;li\VI<.-\\'. If. f"{om.:.Mr:-.oN, :.!!l, Tfl\\.1itc·,·flf,., ,\ rmwthw.dlt',

\Vhitc·ha,·r11, l'urn"b(orl:uul c;•n·,, \ . B. s1 \JO'"-· F111u, r.1. Urit, J, 11t• l 11·", 111. \\'hutr''

B.1\·, Xorthumll('rfaud. (~t•I.\'.. s. s. c. f !"\,\f<;, a. :.;t.rnwar ( •. ud111 ..... \1 (1111, l.011do11, \\ .a. <;sue I L ~I. Tarn, 10 1. llrc to ry llo.ttl , 1J11rlll1·)'. L>nrs. C~Dll. - R. T UNN'lf \', a7. Mnulow l<o:-.d , lk>t''\ltlll, Sou ,., (;•H.<~ L. II. (;MA\'," Four \\t1nd~," J),..,.,.,ni1..h Ho.HI, Sui)n111a,:cl.•l1•,

11.r~--(i:-> Pf I'. HA L11t.1 \, ~. Pr1111r" <~:-.nl111,, E.11111~. l.11ndoo, \\ ,.i. C~i--J'~I J. f), )IAt"h'.AY, i· o hh11f'.ln•, I t'. Jh·tht· ~totml, \\'(•h\\'11

<:.ode11 City, fl l·1·t .... • ' t;..,:J{U, .A.. F..\f ll1CJH, "Ohm .. J.u, ," ."):.!, \l.a ttlu•\\ .. :'->tr•·t•t. :\h'n .. 1011,

l lrrll\'. <.rt.rJ .. .\. GAM,Ot h. Jo~t ... :J:!, Ho~.utl1 1~1,HI, 1.ondou, ~ \\ .:;. :?-\FO. :\ . .-\ Owt·1', I:!. Ur.ulin,: l{tl,111, Hr1,.:ht1m. ; , Su~"t'~. :!:\I I. ,I. O:n\AJ 11 lh"Kt", 1: •. J11tl11 .. 11w f{oul , Broad ~n.v·u ,

l.1\t·rpool. :.? \l'Q J>. f{nu >t, .l:•. llt\\ood l~oJrl, \lkrtou l.1\trpotJI, Ht. :!A\'t' H. (, \I ft\11 'H'· :?:!~ \ t• 1''1't-a R•l.l1l \\'nod C1r--f'n.

l.t•ndc1n, :-.; !!:.! :!Hf)I<. j. R. lh •R1n~, M,.m Stro 1. ~··~1~r.t\1·, llf•ar I ou'(h·

l1on1~J1, l .-u .. :?U\tf\ \\"" · ft ruo\0''0' , Fl .. H 1, hrt ~t:lll<m. l'.ara<lhe Mrtt'l ,

\\ •'l Brom"" h. ~1:itf, :!B(h .\, S-r" t '. •· \ fonnu," Go·.)ft•r&t I.ant· l>runnelJ '.!BHO J •. \. l>ouo;, ~I. Ou· Ro"I ( r.-.•·cnt, Slu·ffatld. :!C).I:\ ~. \\' 11\'\'Fl., 2.a;;, C~t·flf'\',l Hoatl, llotrhnJr:ton, Co. 1)111h.uu. :!CO.\ C \\'1t11.11r. 7, lire• klt·OO.nk rto.l<I. ~loau ho tor. H :!('\\ II F. Jo~•• ~ t'oa t~~· Croo•hall H•ll C'ooa-horou~h a11 ar

f)t,.11 .blf'"r :?l YI \. A. jn,1- ... • I .\'ndhnr .. t.'' \\ .un·n Lt1h· th;iprhu\\ n.

II• .u Sht>ltlt<ld. :!CZC. J. \\0

\R1t, 1:10. Cu111dl l{o.;ul, ~hf'lttt·kl, ~ :!I)(;;' !-\ )lfHU•\, 'Ml. (hurrhcl.&Jf f{n.~J. rr1·t hf·\•illf, llt·.u

~hrJhc.ld :!Diil ~l- \JLl i <cut\I\' :!t:J, IJ4""Clrroul ll11J, '."\trc:uham, 1.on

thm. S.\\ r11 :!D IQ. .\ . H. f, Yut M:, l luhcm Pohl111 \ 'irar,l.:1•, Britl~w;u1•r,

Som. :!I>:\\' <:. In" ... HJ. llob.ut Strn·I, ~htlflthl :!DO\\ • ..\. ~ f-.• <'nM""l:o-11, Cr"" bt.·ar ( C'tl3J::f"', 111 .u Torn1u;tc.tn,

~- J)f','(lfl,

:!D l'IL H. H. Hw1 :"t. IHU 1 , HC'nul11..:co11, Dr.l11 Hm,, \\1ih11 l'>l~m·, nw.-.

:!UJIJ . S1nH11111 S,\\". t 11 ·u. ( Juh J(•lc')m .... LlJt11ot·r Sirt"t"t. !'h:tlt• ... moor. ~htlhrld. :t

:!J>;.\fo' :\. Bnu ru , 11;.;, IHtl"ibun • l<o.ld, l lf,HOfl !\••rn.,, Sux k1)ort, \.0

ht·~ .. :! F D>J . C J.rn .., 10N1-;, t ti. l'lrn lton l )1h1" Londun , N. !!. :? FFN. S. C. F1 .. 11 f<'u, Th.1111r \'irw. lhlbich• Ho.acl, lii111·ru .n-.

Luc-~. :!FH\' F. 1.. Host., 14, P~rkway. Rl\'111, ParJ... 1.ondon, !'!! \\ .~O. :!FI %. ~h~~ MAkJOM1 P' I\. CH 1 A<\, ':':I, Fon~ ~tf"t>c•t. Sakombc.

s. l>c.•\' 011. ~FlM -J. B l{o .. rol!. 5\1, {'1oh'\n1 J(o.111, Smtth ('1ovdoa, Surrey. 2F1'\l J>. I'. I... \hY, :!:!:S. ~rh<'lnllo11 J(o.l•I, l hnrn ton H.-;uh ,

~\lfH''" :!'FI\'\' ·A .• .\. Pt ut '· U, Broom fr• ... •·HI, 01 tuhrN•, .\\T .. htrt'",

~'otl:rncl. :.?FI.I\ T . l.. 1>1 L\'I~. ·n,,. <.r("\'hOHIHI llOtf'I, lhl(h H.oad, l.h.ul

\\('II Heath, E~Sf'' :?F)l( ~. \\' l'UN!'"Lll, ;}..",, (it~· J.to•il :-;,Jr\\f h. " orfoJL :!f')IX I' P llu\IU \, 0Jklrai:h, ~INr•. nr3f llurton-oo I rent

StdU~. :!F~~I <;. <~. EA'T'' 1c K·l•'u 1 n, Jlrinr', llat\;h, t.odalmin~. Surrt'"\". 2fNt' -J. A. , .· ,~11 RHMOOK, M3rflt·lfl, r:uif·~rll I ;m~. Sh1ph:H',

ruu1u•n-. ~FS-\\" J I \\'A•1t1".10,, fht- J ffn ... lM~t<·n, u.aLbam. Rutl.md. t 111c.tlltJ. 1.:11>:-I, :!AAO, :!Af'Q, :!.\I.II, 2A I I 2AXG, :?AX\',

211NB. W\'G, 2nx:.-. :!CBA, :!( 1111, 2CIX. :!CGO, :!C)IG. ~ kj , :!<.HN, :!CSF , ~C.: XC, 2CXI>, :!CYJ , :!l>Bli. :!JX;Q, ~Ill;\', 21lC\\' ZllllA, :!IHL, :?lllo:I :!ll:O-:X, 20:0-:\'

,

3 16

AUTOMATIC BREAK-IN SYSTEM - (Co11/. /rum p. 273).

5 nulliampcn·,,, a clll'ap 11 .T battery will operate it for month,. .\ltt'rnat1\·{'f\· .rnotht'r rcla\' 'inular to :\o. I can be used 1 r dc,,ircd. Th er<' 1' iw reason why t he sa m e batt t·ry s ho uld not ,,11pply the cncr· g1~ i11A' \'Olta;.:c fo1· bot h rc>la\'" if t hey arc of the sam e typ<:

Adjustment

The adj1htment of the w:,tc>m " ahnc"t *Jf. explanatory So I rc>l,1v -mu,,t .Ix· adJ11,tt'd ~11 that the contacts for the rc1·c1,·er arc clrn,t•d when the re lay is not t' ll c rgist'cl. Apar l from th is. nu furthrr arlJ11stmcnt ,houlcl he nccc"ary. cst·ept for the r<·1·cin•r lilter ro11dcn,l'1 \'alul'

\ \ h1·11 tlw rccei\'t'r. tr<irhmit ter ,1 11 cl momtor arc sw1t.;hed on and aclju,tcd. the n·n·1\'cr -houlcl !?O dead, pro\'iclmg all connl'• t;ons h.l\c het•n made correctly. "hen the key 1" pressed \ C \\'. signal sho11lcl then be heard Ill th1· 'phone'' wi th 110 apprec iable clocl<' at all.

\ \'hen h1i;h-pow«r t rnn,1111tters ar,· in uw It may be nec1:s~ary. for the furthrr pro1ect1011 of t he rect'l\'Cr. lo i1i-tal a rt·lar in the aerial ll':td 1war lo the aen.il tcrnunal of the rect'l\'t•r . .;;o th.1t tht· aerial I' abo <11-cor11wned when the k.:y j,, clo:pres,t•1l. For powt-rs u p lo .'iO wa t h U11s is 11ot t•on.;idcn·d neccs ~ary.

. \ f1·w hour:,' operation with tl11s ::.y,tcm wdl pn"" wi t hnn t dou b i lha t n is , .('I' \' sn 1 1~l; 1 ctory For not onlv does 11 remon· the llcl'd for-.\\itchin-.: " h1l1• the ,.1:11um 1-. 1n opcr.uicm. hut ll al" ..illo'" the opcratm to cto other th111,1:s ,,,, ''ell In tht· fi rst plact' fh· can tr•uum11l a ·• ~rc"'t ·· c:all :-,i~nin~ " B I\ " frcq11t·1nlr and tunt• o,·er Uw hand \\ithout ex111.·ncncin;.: bad l' lieks or thump, <Ill)"\ hen• . Second ly, i i b possible to n'ply to .i .. T .. st .. or "(Cl" call . an<l to con1inui: to clo so 111ttil tlw ::.tadon arh\\ers. or 1-. hcarcl t» arb\\t·r ,unw other :sratton. wlwn trar1'1111"1on' l'an at llltlc swp. thu ... s:wing much t imc•. In till' llurd place, It makes po.;sihlc a .:ontact "111..:h can be cont111ul'd .1t will. ancl "l11ch l'an be broken 111to at anr 1110111•nt if ;1

word b misH•d o" ·in/.( lo ja 111111 ini;:. F inally. it can be usl'cl 011 any frcq 111•ncy fo r which the st:1lin11 i,. liccnsccl \\ithout any alteration whal<'\Cr

A " HAM " HOLIDAY IN HOLLAND -(C 11111 ;ram p . :IO I ).

that proved lo be most inkrest ing. :i nd 0111· wh ich shoulcl not lw mis ... t·tl hy anyone hanng tlw oppor tumt \'

On other ucca~ion, tinw w:b Sp<·nl with I 'AUPU. PAOJ ~I . l'.\OXF. a11el with the I laarll'm ' cction of th•· :-\ \" l.R. 5ti '.\le. an"·it\' 111 ll,1.11lem j,

consiclcrabi<:. and ' 'ery l{ood work crn l hi,, f 11•quen.:y has lwen do 11c in 1h i~ :1nd lll a 11\' rnlwr part~ <> I the countn·

Al la,t tlw tinw < ;1mt• tu •.3\' good-bn· to t he Dutch friend, who had done• so much to 1•n::.urc the 'ucce:-s and enjonncnl of the holida\', .111<11t w;i.

with the i:reate,t r<'gret that lcan·-t:il<111g' wer.mack . . \ ft1•r leav1nl{ l\l r. a nd ;\ l r,, l',\OjA a l R ot t t•nl:\111. (;6HF a ncl h is wife sa ili:cl fur Hu ll with the firm determination to Ix· hac k a/.(ain in PA :!' .. soon a, opportunity offered

7 HE T. &. U. /JULLET! .\', :\n\·embt7r l!:l.11\.

VALVES 955 acorn, 25 /6.

no, TZ20, 17 / 6. T40, TZ40, 24/-. 866, 10 / -. 866, jn r. , 7 /6. RCA

IMPEX First grade American. 5Z3, 53, 59, 79, 89, 46, 83, 5 /6. 6L6. 6V6, 25L6, 6A6, 6K7, 6N7, 6C 5, 6 /6. 80, 4 / 6. SO, 10, 8 / 6.

S.W.R. S T A N DARD 19-in. RACKS AND PAN ELS.

R.icks ~re of hu -ty cauic I l-1n . stC"tion anife iron. Chusls are 17 tns. x 10 ins. x 2 Ins. All are finnhcd hard stove enamel. P•nels are he.vr·&auic steel. <rack le finished . A comple te R.;ick to u ke th r-ee fO~ -in. pa,nels ;nd one 3 ~ -in. meter panel, wit h t hree chsuls. • lt br>cken , bolts, etc. £1 14s. Od.

Carriaie E>etra.. Alt parts un be supplied separ>tely.

35-in. Racks £1 2 6 7-in. Pane ls 3 0 IO~ ·in. Panels 4 6 3 !-in. Panels I 6

Ch•uis and Brackets, S / 6

Authorised S to ckists o f H ALLI C RAFTER RECEIVERS

Super S ky-Rid er, £32; Challe nger S X I B, £15 ; Sky C hampion, £15 ISs.

H.P. Terms civo1/oble.

All EOOYSTONE COMPONENTS In stock.

Send lor lisu .

SHORT WAVE RADIO, LT D. 97 PA RK LA NE, LEEDS I . T el. 24689.

AERIAL WIRE ! ! ! H2ve you tried the G6US OX Aerl2t W ire ' Do ze ns o( tcst imoni~ls.

Cu t ltn1th1 or ~ny spec11I lcnz.1h to order.

14 g2uie enamelled, Semi-hard drown 34 It .. I /9 : 68 le., 3/- : tH It., 6/·. 12 g•u,e. H h .. 2 /3 : 68 It., 4 /· : 134 It.. S i· ·

PYREX INSULATORS Genuine Pyrcx 1bn. 3! ins. lone. 450 lbs. brcakin' scriin. Pnce 9d. o.c~. Po" l d

Pyrex Le ad-In Dowis. Sm•ll p•t1ern. I /3 u ch.

N . E. READ, G6US, 24 Church St., Oswestry.

,- -------U N IV E R S A L--- - ----.

MODULATION TRANSFORMERS PRESSED STEEL CASES

SO WATTS, R.mo1 .92. 1.04. 1.18, t.30. 1.47 and 1.59 - • • 17 6

100 W ATTS, 6 ratio• to roquire mcnu 27 /6

TAYLOR T U BES T 40, T Z40, TlO. 866. >nd 86~ JR. JO HNSO N Tnnsmit1onc Valve-holder: 4·pin or

Octal. t /4 ; 6·pln. I f· STANO-OFF INSU LATO RS, I In .. 3d.: 3 In.,

Unbruk>ble 8sH, 11· THROUGH PANEL INSULATORS: I on., 6d.:

11 on., 8d. : I I In. IOd.

Central Radio & Television Ltd. 70 OTLEY DRIVE, ILFORD, ESSEX

Trade' and Ovtrstos Supplied Phone: VA. 3891

!III': T. 6- Ii. BliU.l.rI.\". Xovember 19:!8.

EXCHANG E AND MART. RATES.

Members' prlvat e :idvertisements Id. per word, mlnlmum ls. 6d , m aximum 10/ -. T rade adverlisements 2d. per word, minimum 3s. First line, U desired, will be printed In capit:l ls . One inch Semi-Displ:iy, 10s. per insertion. Terms: Cash with Orde r. All copy a n d payments to be sent direc t to Advertis ln i:i Manager , P:u·rs, 12 L, Kingsway, London , W.C.2, n ot la t er than tl\e 30th of the month fo r t h e fo llowing month s issue.

ASSISTA~T rt .. '<juired, Development Department. Send detail., experience, salary rcquin·d. <'ll

-li--vrcT1\ H.\1>10, I.TD. , Parkhurst Ho:1d. '>'.7.

BAHG.\l':\S from GSAI{, Sunderland. Tohc:. as new, f,7 llh Also 10 to 100-walt ;\fodulalor

with \ ;\13 output, complete with 500 500-300 mill pack, 9 gr1'. This job has just been complctccl . components co'l £ 13 I ls. 6d .-GSAH, 10, Angrovc Gardens, Sunclt•rland.

CLF\l{A':\CI, OF SURl'LliS GE\I<, mchtly rx components. Several Tung,ram vaht•,

1n original cartons, a lso various .\merican valw~. :\lain~ and Audio Trnnsformcrs, Condensers, ck .. io dear, cheap. State wants. l require 7 llk Cry~tal ; stalt• price.- Box 55, " l'.\1<Rs."' 121 . f{ing .way. I .ondon, \\".C.2.

r)B20 l'H.ESEl.ECTOR. 12 mont hs use, :b

new. £ 10 cash.-Ref. L G. ~ew fl ousc. Hatton Garden. E .C. I.

FOi< S.\1.1·. Ecldy,tonc Kilodyne Four Battery model in Cabrnet. with coils 10- IHll

meter .... £4. E\'ershccl 1000 '" 30 m 'a Gencratc1r. with '..!3() ' I) C Drh•ing ;\lotor. d1rcct-<:ouplcd or -.epar.nc. Offer- \·arious other gear for ciJ..,po,al l'.ut1rula rs. 'tamp.--C2X\", Stourton. Stourbrrclgt·

GSC'P ch"p<hrng of thr follo,,ing gear :-2000· 0-2000. 250 :'\[ A ·l\' . SA. 12V. 6A. input

230 50, 50 Cyck•<, 30~ . . L .F. Choke fo r above. wei!(ht 15 llh. IOs.; .-1 ;\lfd. 2,000 \·olt wkg. IOs. All carriag1• forward.-33, ;\!anlcy Road. Sale. Cheshire.

G6DS.-1'nown the world over for quality. QSL Cards and Log Books. Send for

samplcs.-QRA, 14, Lam bley Avenue, Mappcrlcy. Nottingham.

(' 51\"l'.-ATTl{ACTI VE .N E\V DESIGNS QSl. 's. \ J Finest quality. lowest prices, samples will convincc.-State G, AA, BRS. S\\"1..- 33. Howard Hoad. Westbury Park. Bristol. 6.

HAl .LlCRAFTER, Sky Chief, l\larcb, 1938. Extras filled include electrical bandsprcad

Provi,ion for using extension speake~. l lardl\· used, absolute!\· as new. real bargarn £8 5., -G3NQ. 7. Dcbcn Avenue, ;\lartlesham. Suffolk

" H Al\1-Al D ·· qSL"s arc best for design and rolour. Samples from G6XT.- TiLLOTSOl>

BRos . Commt•rc1al Street, ;\lorley, York,,.

I ~!PROVE the efficiency of your Transmitter by fitti ng the co ils used by the lc<HJ ing .British

" I lams." ;\ir spaced and rigid. Diameter$ 2• to 4", 12 or l4 SWG. 2d.pcrturn. \\"riteG;\130:\1, "Gowanhill.'0 Drip Road, Stirling, Scotland.

\'ii.

\ A OYI':\G C0£L ;\IILl.lA:\l:\IETEHS, 15 · l'ach, 1 VI worth 22/ 6. Instrument wuc halt ordinary prkc;,. 25 \\att Transfonnc~ 10/ 20/ -1 0,·. output 7 <l, lcat1et free. Complete EI...-ctncaJ Cat,1logue 4d.-Wrt.KT~so:-:'s 20-1, J.o\\cr .\ddiscombc Hoad, Croydon

OLD-TT:\lEHS.- Ha\'C' a ~pccial <JSL. l' irsl Gracie ~}SL's, new design~. Stal<' G.AA,

!IRS. S\\' L. Samples from G6;\IN.

OSL's.- 250, -ls. 6d. 1,000, g,,_ l'o~t free ,...., Samples grat is. Stale whether BHS, J\A.( ~. ATKINSO~ llRoS., Printers, Elland.

R:\!E 69 with noi:.e :,ilencer and DB'.!11 pre· selector, perfect condition, <.O't ! 5-1 . !><!II

l:ltt. Ta>•lor Tubes. co1nplctc with hl:unent transfs. 756, 25s .. T55 -IOs. Xlal ;\!1kcs, 1\ ">tatic :~·:_1. £3. DI0-1. £'.~. ~-T. tran~~· .,_t I 00·,~:1100. _;iO mas .. £ 1. Chokes. _.,o ma;, l _._;iH. 1 _., 6d .. ~lOH 12s. 6d. 70 watt ,,peech amp and modulator. 57. 57. 2-2.\3. -1-16. Thordarson transk. modu· lntion transf. T6699. Ferranti 0-500 ;\IC. meter. '''rth complete power supply, cost over £ 1H, ~ell £7.-G:\12lJI,;, 29. Gcor,i;:c Street. Stranracr.

SINGLE SlGXAL SUPEl{·llETEHOUY:-;E. 2 Volt Battery Model, comprisi ng prc-:,clcctor.

lst Det., E.C. Oscillator. Hcgcncralivc l.F, 2nd l>ct.. B.F .O., and Penlodc output ('witched). Circuit and Chassis as ~hown in J\ H.RL Handbook, page 13-1 . Aluminium Pand a nrl Screening Boxes by Paroussi, Hammarlund l.F.'s, l}lttl Oak Cabinet to fit. Coi ls for 1.7. 3.5, 7 and 14 1\ lc. Abo B T.H. Trans,·erse Current nlicrophone with ,land and transformer. l\lu~t be sold. What oilers ?

Cl\lsnr. 361, Brook Street. Broughty Ferry, Dundee. Argus.

"T & H. Bl:LLETI);S" for sale. \ 'olumcs l to9, • complete and rn t;ood condiuon. -10, · or near

ofTcr.-Box 79, R.S.G lL 53, \"icloria Street, London, S.\\'. 1

\TARDl.\TCH _I TR.1\:-;SFOlOIER. ?.Os. AF.iC. 10s. Genume !;Calcd R.C .. \ fubc~. tn>e

4 1. 4~. 6d. 53 5s. Gel. :\!any othcn., ;ill 111111-.e.l C6Qj, -19, Clifton Road, Liverpool, 6 .

'

l Tllr\T Of'FER S? Kew pcrfct·t commercial· IV made 230 v. A.C. 350 , ., D.C. at 100 ;\! / a .

550 ,._ peak smoothed. metal I<ccllfiers 6 v-7. 5 , •.. 2.5 v., 2 amps. C.T. metal case 7. Bcddrngton R'>acl , Se,·cn l<ings. Essex.

£2 5 OH EXCHANGE LIGllT Ci\R.-50 wrLlt 230,·. 50 cycle Transmitter l'rofcssionally

built to .. ham" requirements. Co't £15. Standard P.O. Rack and Panel C. \\".-·phone --1!ntirely band switched 20m. to 40m. in 5 second~. ;\l.C. meters in ever)' circuit. Crystal Selector ~wi tch . Speech amplifier plug and jack input for crn,tal or carbon mike and ~ram. Three power pack~. Remote ~ontrol for ;;end-recei,·e. - GRIFFITll'i, 296, Thorold Hoad, llford.

Patents and Trade Marks. ('EE & CO. (Established 1905). Patents and Trade \ T Marks throughout the world.-H. T. P. GRR, Mcm. R.S.G.B., A.M.l.R.E ., etc., 51-52. Chancery L-inc, London, W.C.2. (Two doors from Government Patent Office). ' Phone: !Jolborn 4547 (2 lines). Handbook free.

-

\'iii .

A simple transmitter which provides an outpu t of approx mately 1.5

watts.

TJIJ; T . .... - R. B U I.LE.TI.\", ~u,cmhcr 19:lt>

Conventional components are used with standard H.T. battery and accumula-

to r.

A PT 7 Batte1·y-operated T1·ans1Ditte1·

f/IJLL DETAILS I.\· TllE N011• ISSIJE 1114,

"TELEV·ISION A ND

SHORT-WAVE WORLD OTHER FEATURES IN THIS ISSUE INCLUDE:

The Television Picture and Interference

Simple Television Transmission with a Disc

New Miniature Cathode-ray Tubes

Mech anic<>.1-optical Film Transmitter

A 2-channel Pre-amplifier Improving Performance of Com

munication Receivers Modern Transmitter Construction R.A.F. C.W.R. Transmitter

PUBLISHED BY

''

NOW ON SALE

PRICE If- Fro m a ll N ewsagents a nd Bo o kstalls

Bernard Jones Publications Ltd. Chansitor H ouse,

37{3$ Chancery Lane, London, W.C.2

rrinl• .tin r,r :u Britain forth~ •~c. RADIO Soe•nT or (i1' 'T l'hun1 ... , SJ· \·ir1ori.• ~Irr~•. I.Andon. <;.\V.1. h~ l.<>" lY BR0TI1tas. LTD .• .so. Sou1h.,·:irl: llridit• Ro•d. London. !';.F..1.

~\'1(4~ - World Radio History

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Transcript of ~\'1(4~ - World Radio History