In Australia

Here's a special report about the Twin Ciiics Radio and Electronics ClubT Inc. s Year 2000 hamfest held in the city of Albury, NSW, Australia.

Through the ingenuity of All VK3CQE and John VK3LM, everything was arranged so thai W87XT in Cincinnati, OH, LISA, could view many "live" scenes with pictures and sound from the Twin Cities Hani lest in Albury. NSW. Australia, which occurred on August 13th, 2000, Voicc and pictures were made possible by utilizing VocalTec [Phone 4.5, an Internet voice-video software program. We believe a first may have been accomplished in this regard in connection with amateur radio hamfe sis.

Background

W8ZCF made acquaintances with All VK3CQE and John VK3LM

Sue Thurgon
Photo A. Aif Coupe VK3CQE, first picture received by W8ZCF of Albury Hamfest.

through a mutual friend, Don Miller W9NTP of Waldron, Indiana. W9NTP and his wile Sue W9YL (now a silent key), had toured Australia by motor van, operating mobile under the call VK2IKZ/M They had circled much of the coastal area of Australia during an S-week tour beginning in September 1997. During this period, due to band conditions, Don could seldom be he aid direct in Ohio, USA,

VK3LM acted as a relay via 20 meters to send Don's 80m and 20m SSTV pictures to W8ZCF. During this time, contact was also made with Aif, and SSTY exchanges have continued between these stations o\er the last 2 years. Many excellent, often "studio-quality." pictures of the people and landscapes of the iwo continents ha\e been exchanged on 20m SSTV.

A few months ago, Alt and Farrell began to experiment with PaiTaLk, a voice/video computer Internet software system. They were able to attain only a partial success, with one-way excellent audio from Australia, but the return from the USA had to be via the keyboard. Aif, being the experimenter and "wizard" for which he is nicknamed, suggested a try he made with

VocalTec, anoiher voice \ ideo system. Assisted by 20 meter contacts to set up and make adjustments between the two stations, VocalTec I Phone 4.5 has been, most of the time, very successful. Exchange of "live" moving pictures on a once-a-week schedule has been maintained over several weeks. Pictures sent by both stations are 320 x 240 resolution, which produces about a 9 xl2 cm picture on a 17-inch monitor set for 800 \ 600 pixels. In the program there is also a provision for sending \cv\ high resolution still pictures through a "whiteboard," These pictures transmit very quickly, in a matter of seconds to

Photo ft. Farrell Winder W8ZCF. typical of picture received at Albury Manifest from Cincinnati* Ohio, 73 Amateur Radio Today ■ August 2001 29
Cincinnati Hamfest
Photo C Greg Sargent VK2EXA.
Cincinnati Hamfest
Photo D. Bau e Mitchell VK2AYM.
PAflio E ßm/rt ß/dl VK2TGS,
Phow t\ John Wilson \ K3LM

a rninule depending on the actual resolution, and provide \er\ excellent quality.

Invited to the Aihur\ Manifest

With the above success. A If related

30 73 Amai&ur Radio Today • August 2001

that he and John VK3LM were going to do an SSTV demo at the Alhury Hamfest on August 13, 2000. aiul that W8ZCF was invited to attend using the VocalTec experimental system.

Alf set a time, explaining that he would first shoot a series of Olympic oreh pictures from that morning as the runners proceeded down Ford Street in his village of Beechworth, Victoria, He would then race to A I-bury \ ia automobile to >et up for the schedule.

Success!

Alf completed hi> Olympic mission. Precisely on schedule at 01:00 t TC, 9:00 p.m. USA and 11:00 a.m. Australia time on August 13th, 2000. VK3CQE appeared live on WSZCFs computer screen!! So with all the available high tech arrangements, ii was possible to watch an August 13th show on August 12th!

Alf presented a series of shots at the hamfest using a small low resolution camera connected to hi> Packard Bell computer The picture of Alf in Photo A is the first picture received in Ohio. Typical of pictures seen in Australia from Farrell is that one shown in Photo B, W8ZCF was using a Debco Computer with an inexpensive Intel PC Camera {ProPack Version),

The connection to Australia continued for almost two hours of picture and voice exchange with many attendees at die show who came by fur a look at the experiment. The connection to the Internet was provided h\ Ross Wheeler VK2DGY. who owns and runs the Alhury local Internet service provider. Ross gave free use of the Internet and the arrangements for the hamfest experiment were made between himself and Greg Sargent VK2EXA of Alburv. All of us involved wish to thank them \cr\ much for their generosity Greg attended the show, and his picture as received in Cincinnati is shown in Photo C.

Many other visitors came by. QSO J through All's setup, and made their TV debut! These included Bruce Mitchell VK2AYM from Lavin"toa, NSW, shown in Photo D. [t may be noted that Bruce has a "Boarding

Photo G. In GUmville VK3AQV.
Photo H. John Quarel VK3HJQ.
Cincinnati Hamfest
Photo I. Hayden, future ham,
Alf Amateur Radio Photo
Photo y. Alf Coupe VK3CQE, with Kodak DC 290.

Kennels'7 operation as seen from the logo on his shirt. Brian Dick VK2TGS of Thurgonna, NSW, is shown in Photo E.

John Wilson VK3LM of Tallangatta Valley, Victoria, is shown in Photo F

Photo fi John Quote! I K3HJQ m computer, ami John Wlson I k'JUlL
Photo L. The computerAtocalTec ¡Phone setup,

holding an SSTV Interface Box, This a VK3LM design and was offered as a kii introduced ai die show. The interface does not use a computer soundboard. (Details of this kit ma\ be obtained by contacting John Wilson at | [email protected] |.) To note how fast technical news can travel, combined with amateur radio, this picture was shown local Is on 2 in SSTV the next morning in a portion of the Ohio/tndiana/Keniuck v. USA, area.

There was immediate interest bv two chaps. It was later in the day transmitted via 20 meters to Don W9NTP/7, who was mobile near Winslow AZ. Don also expressed much interest in VK3LM"s development

VK3AQU, In Glenville of Myrtle-lord, Victoria, is shown in Photo G. Photo H is of John Quarel VK3HJQ from Tallangatta. Victoria. Note the small toddler in this picture who has come for an early introduction to hamfest activities. Photo I is of "Hayden/* perhaps a future ham operator. He seemed to prefer a close-up shot, perhaps trying to get as close lo the USA as possible!

Photo J is of A If with his Kodak DC 29i) digital camera, preparing to take Photos K and L. After Ihe pictures were taken they were sent via the "whiteboard" as explained in the above text This photo shows John's and Alf's booth, with VK3HJQ posing for a picture. (See the cop> of the actual "live" picture which was received us Photo Hj VK3HJQ is again shown in Photo L, along with the VocalTec (Phone setup. The small "balT-shaped camera on top of the computer monitor produced Photos A through J, which were recehed in Cincinnati. OH. Alt s Packard Bell computer and the microphone used to converse with W8ZCF are shown to the right of the monitor

For "amateur' performance, we believe this experiment in showing live pictures from one side of the earth to the other must be a "first" for amateur radio hamfests. It was very successful, leading to much fun and excitement for all the participants and observers. In fact, W8ZCF definitely had the feeling of actually being there!

In return for the Albury experiment, it might be possible to set up another experiment to transmit one of the "live" forums of the Dayton 2001 Hamvention to an Australian group, subject to an agreement with all concerned.

Those who might be interested in also experimenting with the VocalTec program may download it from ZL3TMBS Web site at: [http:// wwAv.qsl.nel/zl3tmb], It is currently a free program, but good for only 7

days. It may easily be refreshed b\ the procedure of downloading to a saved tile, uninstailing at the expiration date, and then reinstalling from the file, making it good for another 7 days.

Also supplementing amateur radio activities in a very broadening aspect of the hobby is the inclusion of VocalTec installations into many repeater stations around the world For example* such repeaters as ZL3TMB-R. Chnstchurvh. New Zealand; G7\\~FM-R. Nottingham, England: K5WH-R Houston. Texas. USA: and many others are currently set up to operate on a ver> frequent basis. Experience with these repeaters has resulted in excellent, enjoyable "DX h contacts that, in communicating performance, is comparable to operating though local repeaters with local contacts. The concept of combining with programs such as VocalTec should serve to strengthen amateur radio activities and contacts around the world.

LED FLASHLIGHTS (and moreí)

Colors: white, blue. red. and green D & L Antenna Supply Co-

Secure Ordering On Line ai www, wavehunter.com 1-800-965-8880 Prices from S4.95 to $59.95

• Lasts 4 times longer than regular flashlights

* Lifetime warranty including LED lights

• Features 4 high intensity LHD

lishts

* Pow ered by 3 A A alkaline batteries

After continuously being turned on for 14 da>v (336 hours), it was possible to read a newspaper using only the output from ihis amazing system. This item sold out at Dayton!

Dan Metzger K8JWR 6960 Streamview Dr. Lambertville Mi 48144-9758

Part 9 of good stuff from The Hertzian Herald.

All about More Troubleshooting Tips; Unit Men, Part I; and Unit Men. Pari 2.

Here are ten more troubleshooting tips to add to the ones we have given \ou before. As betore, send me your Favorite tips, and we'll do another len in a few more months.

1. When troubleshooting a printed circuit board, shine a light on the hot-torn and view the circuit from the top. This will let you sec the circuit tracks and allow access to lead wires for your test clips,

2. Metal transistor cases and heat-stnk tabs are nearly always connected lt> the collector, and pro\ide easy-to-probe spots for checking voltages.

3. If a confusing or nois\ trace appears on the oscilloscope, switch the trigger source to AC I INF.. If the trace stabilizes, the noise is AC-line related,

4. Solder less breadboards are often ruined by forcing thick leads from l-watt resistors or big capacitors into them. Later, when an IC pin inserted into the same hole, the contact is sprung and makes intermittent contact.

Reprinted with permission From The Hertzian Herald\ newsletter of the Monroe County (MI) Radio Communications Association (MCRCA),

Solder an inch of #22 wire to the ends of those fat leads to a\oid damaging your %35 proto-board.

5. Flexing often causes scope probes and coaxial test leads to open-circuit at one end — but which end'! Touch the center pin of the connector to an oscilloscopc's vertical input or a DVM on AC-Volts. The intact end will pick up quite a bit of AC line noise; the broken end, almost none.

6. A wooden toothpick is useful for keeping PC-board holes clear of solder while healing them.

7. You sa> } ou need to measure a 30 meg resistor, but your DVM only ¿;oes up to 2\) megs? First, measure a nominal IS meg resistor (call it Ra), then place it in parallel with the unknown (R\). The unknown can be calculated from the Product-Over-the-Difference formula: Rx = Ra x Rtot / (Ra - Rtot). For example, if Ra = 18.13 me^is and Rtot = 1 L47 mens, then Rx = 31.22 megs.

8. You can often determine power suppl\ current without breaking any uires h> measuring the peak-to-peak ripple voltage across a filter capacitor on a scope. Where t is the discharge time between charging pulses, calculate I = C

\ Vp-p / L For example, if a 40-jiF cap has 2 V p-p ripple and discharge time is 8 msT 1=10 mA.

9. Is the zener conducting? Zenerdi-odes above K V produce a while noise of 5 to 20 mV p-p w hen conducting. If a sensitive 'scope on AC coupling doesn't show the noise, it's a good bet the zener isn't conducting,

10. Of course you can check a silicon diode b> looking for high resistance one way and low resistance the other way on an ohmmeter. But highvoltage diodes (above 1 kY) usuallv consist of several silicon diodes in series internally, so the forward voltage required to get the "low' reading will likely be higher than the ohmmeter s test voltage, and you'll got a high reading both ways. Use a 9 V battery in series with the meter on the DCV range to check HV diodes.

Unit Men, Part 1

In pre-industrial times there was liule need for an exact system of measure. Haiter was the rule: this pig for ifiat stack of hay: my two dozen esgs for the use of \ our plow horse for an afternoon. Surprisingly, electrical measures were just this informal prior to about 1890: 100 Daniel! cells in series for a 150-mile telegraph circuit using No. 11 iron wire was a common rule — no mention of volts or ohms.

Charles-Augustin de Coulomb (French) began the trend toward more exact electrical measurement in 1785, when he proved that the force between two electrostatically charged bodies varied inversely as the square of the distance between them: F = Q1 x Q2 / d;. The unit of charge (Q) was designated the coulomb (C) in his honor, A coulomb is the charge of 6.24 billion billion electrons. We don't often run into coulombs in everyday work because we don't have any coulomb meters to measure them, but the concept of charge underlies everything we do in electronics.

Alessandro Volm, in Ilalyt invented the electric battery in 1800 by stacking a large number of alternating copper and zinc plates separated by saline-soaked cardboard. Prior to his invention there was no such thing as an electric circuit or a continuous electric current. The importance of his invention, and of the concept of electromotive force, can hardly be overstated; yet the unit of the volt for EMF was not widely used until after an 1891 standards conference sponsored by Lhc American Institute of Electrical Engineers.

Hans Christian Oersted (Danish) established the link between electricity and magnetism in 1820 when he noticed that a compass needle was affected by a current-carrying wire. The unit of magnetic field strength (an obscure thing) is named for him. AndreMarie Ampere (French) read of Oersted's discovery; within a year, he had invented the electromagnetic coil and developed a mathematical theory quantifying how electric currents produce magnetic forces- The unit of current, which equals a flow rate of one coulomb per second, is named for Ampere.

In 1827, Georg Simon Ohm (German) developed the famous law which bears his name. Legend has it that, lacking an ammeter, he used his bodily shock sensation to judge the increasing currents due to increasing voltage: "60

cells — that tickles; 90 cells — ouch; 120 cells — yikesT Henry Cavendish, an Englishman, had proposed the I -E / R relationship years earlier in private writings which remained unknown until the late 1800s, when James Clerk Maxwell edited and published his papers. As with Leif Eriksson and Columbus, it was not the one who made the first discovery, but the one who first revealed it to the world who was honored. The unit o\ resistance might have been the Cavendish, but it is the Ohm.

James Watt was a Scottish engineer who improved the design of the steam engine in 1769 by using a separate condenser chamber to cool the steam back to water Thomas Newcomen had invented a rather clumsy steam engine in 1712, and modern high-pressure steam engines were developed by Richard Trevithick around 1800, but Wall was chosen over them to iiavc the unit of electrical power named after hirn. At first this may seem strange, because Watt's work was not in the electrical area. But in the metric system the unit of power — mechanical or electrical — is the watt. The equivalency in English units is 746 watts = 1 horsepower.

Unit Men, Part 2

The capacitor originated in Leyden, The Netherlands, in 1746, and was called the Leyden jar. In form it was a

» DIP switch programmable *Mmia]u?c n size ■ 37 EIA tones. 27 ron-stardard ÎOftes from 33 Q le 2W 1 H i IncJuderi

- Reverse Burst built-in

- Easy 3 wirfl hookup

55-64 CTCSS Fncacer 661* 1 OF* 2r glass jar, partly filled with a conductive liquid, and wrapped with a metal foil on the outside. Static charges were stored in the jar, giving rise to the notion thai electricity was a form of fluid. Capacitors in their modern form were developed by battery inventor Alessandro Volta in the 1820s.

Strange then, that the unit of capacitance, the farad, was named for Englishman Michael Faraday, whose work was not mainly in capacitance, but in electromagnetism and induction. Faraday discovered that a force existed on a current-carrying wire in a magnetic field — the basis of the electric motor — in 182L In 1831 he discovered that a constant magnetic field would not induce a current in a coil, but a changing field would — the basis of the iransformer.

Faraday kept detailed notebooks covering decades of meticulous experiments in electricity. He did not have the mathematical talent of other researchers, and wrote touching letters begging them 10 put their results in everyday language so he could incorporate their insights into his experiments.

Joseph Henry (American) had discovered the transformer principle a year earlier than Faraday, but Faraday was the first to publish, so the credit is given to him. Henry developed an electromagnet capable of lifting 750 pounds

Continued on page 61

SS-&4 DIP Switch Programmable CTCSS Encoder SZfl 95

• Supports 157 Ripper Subscribers

• On-Ltra Computer Help

• Aar Tinia Lining & Analysis G^pfts - Signa !lng Formais CTCSS

Continue reading here: Dcs Otmf

Was this article helpful?

0 0