Amateur Radio January 2009
Delivery expected from 2 February
Editorial
Another New Year…..
Some changes are about to happen on the world stage, most notably in the US with the inauguration of Barack Obama as President. I am sure that we will all watch with interest to see the resulting changes.
With the financial melt down that occurred in the second half of 2008, many are forecasting doom and gloom. Some advertisers are saying that they are (or have already) reviewing their plans. For example, Vertex Standard (Australia) has decided to withdraw their display advertising from Amateur Radio. This does not mean that they are going away, simply changing the manner in which they engage with the amateur community.
Of course, another impact has been the changes in the exchange rates between the Australian and US dollars – from a recent peak of around 0.92 around May 2008 to the mid to high 0.60s of recent times – around 0.68 at the time of writing this piece. Depending on how you look at the maths, this means that all things coming from overseas will cost us of the order of 30% more. Many areas of the economy are winding back somewhat, with reports of job vacancies falling significantly and of companies reducing the size of their workforce. It remains to be seen what will be the impact on our hobby – I would imagine that it will depend upon whether or not you are directly impacted!
Over the Christmas and New Year period, I had the chance to catch up with my wider family for a few days. A very relaxing time was one result. The period was largely spent without radio, at least until my return home. Then there was the delight of an Es opening to ZL on 2 m – one ZL in the log and a few that were very marginal that I missed. Such is the nature of Es propagation!
The world above 30 MHz
Many readers are aware that my primary area of interest in our hobby is in “weak signal” propagation on the bands above 30 MHz. I say weak signal, but often signals are extremely strong. Many newcomers to the hobby think that FM and repeaters are terrific on 2 m and 70 cm. I agree – FM mode and the repeater networks provide excellent communication opportunities, further enhanced by EchoLink and IRLP if you have such nodes nearby.
On the other hand, I have heard many Foundation licensees having terrific contacts on 2 m and 70 cm SSB, often working stations several hundred kilometres away under relatively flat conditions. Add to those contacts the delights that come with tropospheric ducting, which is more common at this time of year. Over the past weeks, the appearance of VK7 Foundation licensees on the repeaters in my local area has increased in number and in signal strength. Even greater range would be available if they explored the SSB end of the bands and used horizontally polarised antennas.
For the Advanced and Standard licensees, there are also several microwave bands. One VK2 amateur has been in the local region recently with a work assignment. Being interested in microwave propagation, he brought his 10 GHz system with him. And he had a ball, from all accounts. On one Sunday afternoon, Jack worked several amateurs around Victoria. He has been amazed by the number of amateurs active and/or with equipment in Victoria. I am sure that he will be trying to stir up more interest and activity once he returns to Sydney. Perhaps he may find the time to send us a brief report for this magazine.
Articles and photographs
With the current Field Day season, I hope that amateurs participating have packed the camera as well as the radio gear. We are always in need of good photographs. Brief reports are also welcome, regardless of the nature of your amateur radio activity – Field Day participation, a Club activity or your latest project. Remember that guidelines are available on the Amateur Radio pages on the WIA web site – under the Members area. Of course, longer articles are also welcome – in fact our stock of articles ready for publication is starting to reduce. Get to it folks – tell us about the latest activity!
73 Peter VK3KAI
Cover photo
The five antenna solar power array under construction in outback Queensland. See the story starting on page 27. Photo by Don Marshall VK4AMA.
Table Of Contents
GENERAL
Buying second hand equipment, Jim Linton VK3PC
Waverley Amateur Radio Society – 90 years on, Simon Buxton VK2UA
Index to Amateur Radio 2008, Don Jackson VK3DBB
TECHNICAL
Building microphone preamplifier circuitry and making it work properly in an RF ‘hot’ environment, Felix Scerri VK4FUQ
A 10 metre FM transceiver, Dale Hughes VK1DSH
Understanding and building the OCF dipole antenna, Ron Bertrand VK2DQ
World-leading solar power technology in outback Queensland (Cover story), Don Marshall VK4AMA
Waverley Amateur Radio Society – 90 years on
Simon Buxton VK2UA
The author, who is the Publicity Officer for the Waverley Amateur Radio Society, has pieced together some of the early history of this club, in fact from the 1920s, through the 20th century and right up to the current period, whereupon it will celebrate its 90th anniversary in 2009.
An interesting read on one of Australia’s older, and most enduring clubs, and for a member of any similar club, readers will easily identify the trials and tribulations evident in any club that lays claim to some extreme longevity.
From an amateur radio point of view, most interesting.
Buying second hand equipment
Jim Linton VK3PC
In this article the author gives excellent advice on how to purchase second hand equipment, and do so painlessly.
He explains in some detail what some of the traps in purchasing second hand equipment can be, and what to look for before you actually commit to a purchase.
It is a good advice: read suitable for newcomers to the hobby, and particularly to any Foundation licensee thinking of a first purchase experience.
A 10 metre FM transceiver
Dale Hughes VK1DSH
This is another building article by author Dale Hughes, on how to go about designing and then building a 10 metre FM transceiver.
In borrowing directly from the article itself:
‘this article describes a FM transceiver that can be used on the 10 m band. All of the components can be readily purchased or recovered from surplus two-way radios and no major mechanical work is required to construct the unit. A unique feature of the design is that the transmitter uses digital techniques to generate the modulated carrier signal directly on the output frequency; no multipliers, mixers or analogue modulators are used in the transmitter signal path and this significantly simplifies construction and alignment of the transmitter. The receiver is a conventional dual conversion design with the first Intermediate Frequency at 10.7 MHz and the second IF at 455 kHz. The same Direct Digital Synthesiser is used for both the receiver local oscillator and for the transmitter carrier oscillator; its frequency being switched by the microcontroller as required. Figure 2 shows a block diagram of the transceiver’.
For keen home builders, a most interesting, and well detailed, article.
Understanding and building the OCF antenna
Ron Bertrand VK2DQ
The author gives readers quite a detailed overview of the theory of dipole antennas, but principally Off Centre Fed dipoles, together with an explanation of his views of the various types of balun that may be used in conjunction with the antenna, and why he chose a particular variant for his personal use.
Quite detailed, but very interesting reading for anyone contemplating building this type of antenna, or any wire antenna variant, for use at their QTH.
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Page Last Updated: Monday 24 August 2009 at 13:58 hours
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