hamlarks - Christchurch Amateur Radio Club

May 2006

Christchurch Amateur Radio ClubHAMLARKS

Christchurch Amateur Radio Club. NZART Branch 05

HAMLARKS.... May 2006 PAGE 2



Re-occurring events

MAIN BRANCH MEETING First Wednesday of the month 7.30pm, except January. ACTIVITIES and STUDY NIGHT Every Tuesday 7:30pm at the clubrooms. COMMITTEE MEETING 1st Monday after branch meeting 7.30pm AREC MEETINGS 2nd Wednesday of the month 7.30pm. WEEKLY CLUB VHF NET Every Sunday 8:00 PM on 147.250MHz repeater if available otherwise 147.050MHz repeater. OFFICIAL NZART BROADCAST Last Sunday of the month 8:00 PM on 147.050MHz repeater.

Next Branch 05 Meeting Wednesday 3rd May 7.30pm

Other local Branch Meetings None received

Message from Keith Lyons ZL3AHL COULD YOU PLEASE NOTIFY ME

So that l can bring my Data Address Base up to date for the posting of "Hamlarks". If you are receiving both "Hamlarks" hard copy and "eHamlarks" and don't wish to receive the hard copy, could you please notify me, this will save the club money. Telephone: Keith Lyon ZL3AHL (03) 352-6655 or Email: [email protected]

Cyber Humour - ZL3PI Two atoms are walking down the road when one exclaims, "Oh my, I just lost an electron!" The other asks, "Are you sure?" To which the first replies, "I'm positive!"

mailto:[email protected]



Simple Circuits ZL3KB It can be frustrating when you have the correct value linear potentiometer, but need a logarithmic type. The response from a linear pot can be plotted in a spread sheet, and the output voltage will look like graph 1.

If a fixed resistor is used with the linear pot as in figure 2, a pseudo response will be obtained. This is a good approximation of a true log law pot, and will be close enough for the typical uses such as volume controls, and

applications where fine control in needed at the bottom end of the range. One example I have used these is for voltage and current limits on power

supplies; a log pot will give the user accurate control in the low voltage and current region. If the application requires an inverse log (anti log) law pot the circuit in figure

3 can be used, which is just the same as figure 2 but upside down. The major uses of an inverse log pot is usually in timing circuits, where the pot controls the time constant of a pulse generator and the control calibration in frequency, thus needing a reciprocal function. My thanks to the marvelous MAXIM website for data and graphs shown here. They saved me having to do them all from scratch.

RA

RB

RA RB

R1 RA

RB

R1

Vout

Vout

Vin

Vin

Vin

Vout

Linear

Log

Inverse Log

Figure 1

Figure 2

Figure 3

Graph 1- Linear Response

0123456

1 5 9 13 17 21 25 29

Tap Position

Vout

Graph 2 - Pseudo Logarithmic Response

0

1

2

3

4

5

1 5 9 13 17 21 25 29

Tap Position

Vout

Graph 3 - Pseudo Inverse Log Response

0123456

1 5 9 13 17 21 25 29

Tap Position

Vout



A great Victory for ZL3AC

Well done to the ZL3AC team for their First Place in the Jock White Field Day (80 meter section) contest. Even though we were stuck down in the South Island miles away from the party, we still beat the North Islanders! Well done team, and thanks to all our helpers. Same again next year?

80 Metres Only CALL QSO Branches Score Power Branch Ph CW DX Ph CW

1 ZL3AC 335 177 1 37 53 100700 100 03 Christchurch 2 ZL2AFV 487 96 2 37 49 96089 100 42 Titahi Bay 3 ZL2DS 287 203 35 51 95676 100 16 Horowhenua 4 ZL2AMS 620 8 36 36 69840 100 23 Marton 5 ZL2TO 522 1 37 37 58312 100 47 Waitara 6 ZL1ZLD 392 36 36 42336 100 86 Suburban ARC 7 ZL1LFA 233 31 31 21669 100 78 Far North Districts 8 ZL2AJ 56 20 20 3360 100 13 Hastings

Also congratulations to ZL3VV for their placing in the ZL3/4 Trophy Midland Region 2 band entry.

HAMADS $$$ HAMADS $$$ HAMADS $$$ HAMADS $$$ HAMADS are free to members. Deadline is the third Monday of the month. Contact the Editor with your advert, as on the inside back cover of “Hamlarks.” Please let the editor know when the advert should be removed. For Sale: Unwanted project - Brand new unused Aluminium tube. 5m x 12mm dia 4 off $10ea. Ph 388 2166 ZL3KB Kelvin [email protected] E0204

For Sale: Equipment sale on behalf of Rhys Jenkins ZL3AJK Kamoden Analogue MultiMeter $10, Offers accepted. Phone K Lyons ZL3AHL Ph 352 6655 Email: [email protected] E1105

For Sale Yaesu FT221R multimode 2 m Transceiver base station complete with manual, Osker SWR & Power meter, 5 digit frequency counter & 5 element Yagi antenna, all in good condition. $300.00 cash Phone Bob ZL3WA... 03-3859315 E0306





Tait radio service information

Taits have released to the public some older manuals in PDF that you might find interesting – checkout this web document for details http://support.taitworld.com/main/index.cfm/4,0,76,46,1,html This is a summary of what's available for download. T806 Service Manual [843KB] February 22, 2006 T555 - Trunked Service Manual [2MB] November 3, 2005 T555 - Mobile Two Way Radio [3MB] This manual contains general, technical and servicing information on the T555 mobile two way radio November 3, 2005 T535 Mobile Two Way Radio [4MB] This manual contains general, technical and servicing information on the T535 Mobile Two Way Radio November 3, 2005 T533TR Manual [2MB] This Manual contains General, Technical and Servicing Information on the T535TR Trunked Mobile Two Way Radio November 3, 2005 T530MA - Mariner II Two Way Radio [3MB] This manual covers general, technical and servicing information on the T530 mariner mobile two way radio November 3, 2005 T530 Service Manual [4MB] This manual covers general, technical and servicing information on the T530 mobile two way radio November 3, 2005 T525 Service Manual [4MB] This manual covers general, technical and servicing information on the T525 mobile two way radio November 3, 2005 T520 Service Manual [4MB] This manual covers the general, technical and servicing information on the T520 mobile two way radio November 3, 2005 T498 Service Manual [14MB] April 10, 2006 T377/Ex VHF FM Exciter & T377/PA VHF FM Power Amplifier Manual [2MB] This Manual covers General, Technical and Servicing Information for all versions of the Tait T377/Ex VHF FM Exciter and T377/PA VHF FM Power Amplifier July 1, 2005 T375 VHF FM Receiver Manual [2MB] This Manual covers General, Technical and Servicing information on the Tait T375 VHF FM Receiver July 1, 2005 T373 Aviation Band Radio Telephone Manual [2MB] July 6, 2005 T366 UHF FM Transmitter Manual [2MB] This Manual covers General, Technical and Servicing information on all versions of the Tait T366 UHF FM Transmitter July 1, 2005 T365 UHF FM Receiver Manual [2MB] This Manual covers General, Technical and Servicing informaion for all versions of the Tait T365 UHF FM Receiver July 1, 2005 T356 VHF FM Transmitter Manual [2MB] This manual covers General, Technical and Servicing Information on Tait T356 VHF FM Transmitters. March 10, 2006 T355 VHF FM Receiver Manual [1MB] This Manual covers General, Technical & Servicing Info. on T355 VHF FM Receivers with S/N's 193216 or higher & incorporating the TA-053/1 noise gate.Additional info. relating to the T355/01, /52 receiver is given in T355/01, /52 supplement to this manual. T349/T349A Switching Power Supplies Manual [980KB] This Manual covers General, Technical and Servicing Information on Tait T349/T349A Switching Power Supplies July 1, 2005 T348 Power Supply Manual [1MB] This Manual covers General, Technical and Servicing Information on Tait T348/01, T348/06, and T348/16 Power Supplies July 1, 2005



T347/Ex UHF Exciter & T347/PA UHF FM Power Amplifier Manual [2MB] This Manual covers General, Technical and Servicing Information for all versions of the Tait T347/Ex UHF FM Exciter and Tait T347/PA UHF FM PA. Additonal info. on the T347/Ex/01 and T347/Ex/52 versions is contained in separate supplements to this manual. July 1, 2005 T346 Link UHF FM Transmitter Manual [1MB] July 1, 2005 T346 UHF FM Transmitter Manual view/download info [2MB] This Manual covers General, Technical and Servicing Information on Tait 346 UHF FM Tranmitters. Additional info relating to the T346/07, /17, & /57 is given in the T346 Low Power supplement to this manual. July 6, 2005 T345/Link UHF FM Transmitters Manual [1MB] This Manual covers General, Technical and Servicing Informaiton for Tait T345 UHF FM Transmitter versions T346/03, T346/13, T346/43 and T346/53 July 1, 2005 T345A UHF FM Receiver Manual [2MB] This Manual covers General, Technical and Servicing information on Tait T345/T345A UHF FM Receivers with a 21.4MHz IF (serial no.s 198511 and higher) The above info. relating to earlier versions of the T345 with a 10.4MHz IF is given in Issue F of TM-345 July 6, 2005 T345/Link Receiver Manual [1MB] This Manual cosvers General, Technical and Servicing Information on the Tait T345 UHF FM Receiver versions T345/03, T345/13, T345/23, T345/43, T34/53 and T345/63 July 1, 2005 T341A Transmitter Monitor Manual [669KB] This Manual covers General, Technical and Servicing information on the Tait T341A transmitter monitor July 1, 2005 T336 VHF FM Transmitter Manual [2MB] This Manual covers General, Technical and Servicing Information on the Tait T336/02 and T336/05 VHF FM Transmitters. Additional information relating to the T336/04, T336/52 transmitter is given in the T336/04, T336/52 supplement to this manual. July 1, 2005 T335 VHF FM Receiver Manual [2MB] This Manual covers General, Technical and Servicing Information on the T335 VHF FM Receiver September 27, 2005 T318-02 - Fixed Station Manual [422KB] September 27, 2005 T311 Base Station CTCSS Manual [2MB] This Manual covers General, Technical and Servicing Information on Tait T311/01, T311/02 and T311/22 CTCSS equipment. July 1, 2005 T310/5 CTCSS Manual [857KB] This Manual gives General, Technical and Servicing information on the Tait T310/5 Continuous Tone Controlled Squelch System. July 1, 2005 T310/10 Supplement Manual [1MB] This Manual covers General, Technical and Servicing information on Tait T310/5 Continuous Tone Controlled Squelch System. It also contains the T310/10 Supplement covering information specific to the T310/10 version. July 1, 2005 T310 CTCSS Manual [857KB] This Manual covers General, Technical and Servicing Information onthe T310 Continuous Tone-Controlled Squelch System. Information relating to the T310/5 and T310/10 is contained in a separate service manual TM-310/5 and the TM-310/10 supplement to it. July 1, 2005 T307/AV Handheld Manual [2MB] This Manual covers General, Technical and Servicing Information on the T307/AV handheld two way radio July 6, 2005 T303 Service Manual [11MB] April 10, 2006 T198 Miniphones [8MB] September 8, 2005 T182 Miniphones [11MB] This zip file includes T182A, T182B and T182C circuit diagrams September 8, 2005 T180 - CB4 Service Manual [876KB] August 4, 2005 T162C Miniphone [2MB] This manual covers the General, Technical and Servicing information on the T162C mobile two way radio March 10, 2006



The Challenge – from the GLOBAL SPEC NEWSLETTER

When it comes to the block of ice, who is the blockhead? Question: The question presented in the last edition of the newsletter was: You're with a friend at a picnic and someone brings out a small block of ice to put in the cooler. You say to your friend, "I'll bet you I can cut that block of ice in half and put it back together again as a single block, right here outside, without a saw and without putting it back in the freezer." He tells you you're crazy and takes the bet. Who wins? Answer: You do, of course. (You never take a bet without knowing the outcome, do you?) You take a length of wire, drape it over the ice block and tie a weight to the ends on the bottom. To your friend's astonishment, the wire slowly cuts through the block yet the block "heals" after the wire's passing. You are taking advantage of a phenomenon called "regelation." Certain materials exhibit a lowering of the melting point temperature with applied pressure. Only those materials that exhibit an increase in volume upon "freezing" exhibit this property – like water. In this case the wire exerts a local high pressure on the ice and causes local melting. This water is displaced by the wire and some of it ends up on top of the wire at atmospheric pressure again and therefore refreezes. This is regelation – melting of a substance under pressure and its subsequent refreezing when the pressure is reduced. It's why you can make snowballs (unless the temperature is too low). It is largely considered to be the phenomenon responsible for ice skating, although many theorists maintain that the melting point shifts associated with skating pressures are too small to be responsible. Visit the following URL for a set of pointers to the literature surrounding this particular issue: http://www.skridsko.net/klubbar/data/science.html <http://www.globalspec.com/Click/Go?id=-1989533939&keyword=IceV4I13C&Vol=Vol4Issue13T> And your approaches to winning the bet: "Of course you win this bet. You always win these bets. All of your friends are used to this by now, and the ones that still go on picnics with you fully expect you to show off just how much smarter you are than them. If you are still single, this could have something to do with it. You attach a weight such as a beer bottle to both ends of a thin wire and stretch the wire across the ice block. The pressure on the ice under the wire melts a thin layer of ice, allowing the wire to sink down into the ice. Because you are not adding heat energy, only pressure, the ice re-



freezes above the wire as it is no longer under pressure, and therefore the ice has been cut and then repaired. By the time you are finished, you have allowed all of your food to spoil and your beer to get warm because the cooler has no ice in it, but you have won that bet. I hope it was worth it. If I was your friend, you could bet that next time I would bring my own cooler." New Question: You are cleaning up your boat, which is floating quietly at the dock. You pop open the bilge cover and notice a little water at the lowest point of the bilge. The interior of the bilge slopes upward from this point and has several transverse ridges in it that serve to stiffen the fiberglass hull. You sponge out about a quart of water. Several minutes later you go to put the bilge cover back on and notice that the water is back. This starts to get worrisome! You sponge out the water again and watch with horror as more water flows into the low spot in the bilge, seemingly from a hole in the hull. You wait a while, but the water level doesn't increase beyond a fixed point. Relieved, you replace the bilge cover and resolve to look into the leak the next time you pull the boat out of the water. On the drive home, you start wondering – what made the leak stop? Why doesn't the boat fill with water and sink?

Silent Key ZL1JJ It is with regret that I advise that Dean Jackson ZL1JJ became Silent Key at his home in Christchurch yesterday morning, Tuesday 11th of April. It is understood that his death was related to an epileptic seizure. Dean was just 26. The funeral details for Dean ZL1JJ that will also be in tomorrow’s newspapers are: Saturday 15th April at 11.30am at The Bible Chapel, 66-68 Lincoln Road, Henderson, Auckland. 73 Jim Meachen ZL2BHF



Minutes of the General Meeting

Christchurch Amateur Radio Club Inc.

Minutes of the General Meeting held in the clubrooms at 8:45 PM on Wednesday 5th April 2006

APOLOGIES: Richard ZL3UE, Rory ZL3HB, Gareth ZL3VP. Moved apologies be accepted John ZL3ADF, seconded Keith ZL3AHL. VISITORS: Ron Rowlands ZL3AIV. MINUTES: Moved approval of the minutes of the General Meeting held on Wednesday 1st March 2006, Dudley ZL3GG, seconded Winton ZL3AO. MATTERS ARISING: Nil. CORRESPONDENCE: Inward: QBit, AMSAT Journal etc. Outward: Nil. REPORTS: AREC: Dudley ZL3GG reported on a reasonably busy month. A search in the Mt Aitken region ended with the discovery of the deceased missing person. A week later, a search in the same area ended when the missing party walked out after two nights in the open. The team was placed on standby for a search in the Nina Valley a week later but was stood down soon after. Last weekend a SAREX was held in the Mt Thomas area. Communications will be provided for a major equestrian endurance event at Hawarden over Easter. REPEATERS: Greg Zl3IX reported that QRM on the downlink frequency of 725 was originating in the Riccarton area. Ham and Radio Inspector activity has resulted in the QRM ceasing, but the exact origin of the signal is yet to be confirmed. A trip was made to Mt Herbert to investigate noise on the 725 repeater. Tests revealed that the new antenna was operating correctly but that the hardline coax feeder, while not contributing to the noise level, was in marginal condition with higher than expected loss. The new antenna was temporarily replaced with one of the original dipoles as the mount for the new antenna was thought to be contributing to the noise. The antenna system will be left in this configuration over winter. QSL CARDS: Don ZL3SZ has received six cards in the last month. GENERAL BUSINESS: The aluminium pole formerly used by ZL3SE is available to an interested party. If it is still in place after Easter, club members will lower it for George’s XYL. Mike ZL3TMB advised that a new repeater has been established at the Sign of the Takahe supporting VOIP. The output is on 438.110Mhz. The meeting closed at 8:15pm Following the meeting, Dr Bob Kirk ZL3RK gave a very interesting and informative talk on Tsunamis.



Christchurch Amateur Radio Club

Committee for 2006 email: [email protected]

Ph home Ph work Fax Cell phone

President: John Hirtzel ZL3ADF 352 6323 021 148 9329 451 Greers Road, Christchurch 5 Email: [email protected] V President: Dudley Berry ZL3GG 389 4718 364 2102 027 4364 405 and AREC Email: [email protected] Secretary: Rory Deans ZL3HB 325 4181 1382 Tramway Road, Dunsandel Email: [email protected] Treasurer: Richard Prattley ZL3UE 325 2685 027 435 1013 Ellesmere Road, RD 2, Christchurch 25 Email: [email protected] Committee: Rob Thirkettle ZL3RX 348 3815 364 2510 025 264 6020 10a Ilam Road, Christchurch 4 P.O.Box 6396, Christchurch Email: [email protected] Keith Lyon ZL3AHL 352 6655 2 Leander St Papanui Christchurch Email: [email protected] Barry Waters ZL3BMW 332-2662 332-2642 81B Eastern Terrace, Christchurch 2 Email: [email protected] Don Dalrymple ZL3SZ 332-0747 65 Frankleigh St, Spreydon, Christchurch Email: [email protected] Greg Smith ZL3IX Email: [email protected] Trevor Wignall ZL3ADZ 322 8287 963 9241 021 057 6279 Email: [email protected] Trustees: Rob ZL3RX, Gareth ZL3VP, Greg ZL3IX Auditor: Libby Davis Contact Steve Davis, ZL2UCX [email protected] Hamlarks: Kelvin Barnsdale ZL3KB 388 2166 50 Cardrona St, Christchurch Email: [email protected]

Clubrooms 27 Galbraith Avenue, PO Box 1733 Christchurch Ph: 381 4218
















PO Box 1733, Christchurch, New Zealand

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