Receivers and Transmitters|
The most important piece of contesting equipment has to be the receiver. During a busy contest conditions are experienced that severely test the receiver, and it is important that it can perform satisfactorily throughout the contest period. The most important parameters for a contest receiver are sensitivity, strong-signal handling, good I.F. filters for the mode being used. Long-term stability is a bonus though not so important in a fast moving contest. Extras such as good filters, pass-band tuning and an rf notch are more useful. Oh, and did I mention good filters ?
What is available ?
Most contest operators these days use transceivers or matched transmitter-receiver pairs that can transceive together, but if un-matched separates are all that is available, that should not stop the budget contester from taking part and having a great deal of enjoyment. If you have a good enough signal to call CQ for much of the contest, then separates will do just as well; and with sufficient practice at tx/rx co-ordination, even 'search-and-pounce' can be no problem.
You might be wondering why I am bothering to talk about seperates at all. Well, the reason is that for the budget contester, some very good bargains can be had with ex-military receivers whose specifications are way above anything in the average amateur transceiver, so it might be a direction to contemplate. Your receiver should be the best you can afford, and if your budget is limited, these ex-military or commercial receivers are a very good heart to any amateur station. At very least they make great spotting receivers.
Don't discount the older receivers either - some of these are very well made and have excellent performance that will last for many years to come. If you are not sure of the condition of a receiver offered to you, get a more experienced amateur to check it out, and don't forget to ask for any spares to be included in the deal, thought there are still firms selling valves (tubes) for most equipment. Some of the more popular makes even have their own enthusiast-groups on the internet, where you can obtain service information and guidance.
Although not so easily obtainable, older transmitters are still available. You are more likely to find secondhand amateur transmitters and transceivers, although some commercial equipment does turn up from time to time that can be modified for use on the amateur bands. CW-only transmitters are easier to find and generally easier to maintain - there are many contests that have single-mode sections where you can have a lot of fun. As with any equipment, try to obtain a manual or circuit diagram wherever possible. An amateur-bands transceiver with a poor or faulty receiver can always be used with a seperate receiver if you are careful with the switching and muting circuits. Important characteristics for a contest transmitter are reasonable stability, reliability, a minimum of adjustments, and a clean signal. This is especially important on SSB, where you are trying to be understood; on CW a minimum of key-clicks are vital, and your note should be fairly pure, though the author does remember how easy it was to pick out some of the raspy signals from a pile up that were heard in the days of the Soviet Union. I wouldn't like to suggest that they reduced their HT smoothing on purpose, but then again, one never knows !
An older transceiver, or even a modern one can often be improved by the addition of extra I.F. filters, and anyone would do well to check out the website of International Radio who make and stock a wide range at much better value than some of the manufacturers own ones. (I have no connection with this company, in case you were wondering.) I use a 300Hz filter on my R7A a lot, and find it hard to believe that I used to operate CW with just a standard 2.3kHz SSB filter. Those were the days - you can't even do that on the wide open spaces of 10m now !
Additional comment on the subject of Filters were sent to the CQ Contest Reflector by that master-contester, Andy G4PIQ:
I went through the debate of whether to get the 2.1 kHz set or the 1.8 kHz INRADs for an FT1000MP about a year ago. I took advice from the group and there was about a 50/50 split
between the two options. I plumped for the 2.1 kHz option on the basis that the skirts should
be steep enough to allow the SHIFT/WIDTH control to give me the extra coverage down to 1.8 kHz and beyond. Also I had spent a lot of time in the past using a pair of Yaesu 2.0 kHz in FT1000Ds and felt that the constrained audio response (and maybe passband ripple - never measured it accurately, but didn't look very even on CW) was making for a higher than wanted busted call rate (well - that's my excuse!).
Having now used the pair of 2.1 kHz filters in CQWW SSB I actually wish I'd gone for the 1.8 kHz option. The slopes are not steep enough to compensate and I didn't find the ability to kill QRM off the sides as good as the 2.0 kHz Yaesu pair in the old FT1000D. As an aside, on CW, I added a 400 Hz 455 kHz IRC filter to the existing 500 Hz Yaesu 8.2 MHz filter and this is excellent - much better than another FT1000MP with the Yaesu 500 Hz pair. I must compare the SSB performance across the two rigs.
Many people wonder if a linear amplifier is really necessary. The short answer to this is 'If you are in the high power section, then yes it is !' Even though in Ireland we aren't allowed to run the same kind of power levels as some countries, anything that gets you up to your legal limit will, all other things considered, make a difference. However, the difference it will make is not great, and the extra only applies on your transmitted signal, whereas money spent on better aerials affects the receive side as well, so a budget contester should regard a linear as one of his last, not his first purchases.
Home brewing linears is done by many, as the circuitry is relatively simple though the high voltage and high power components are not so easy to come by these days and it would really only be a project for someone with a big junkbox or access to ex-military or other commercial equipment. Extreme Care should always be taken with such a project as the high voltages involved are very dangerous.
If you can find a secondhand homebrew linear, you'll generally come away with a good bargain, as they do not command a very high price due to the general preference for factory-made equipment, but contains some expensive and hard-to-come-by components that will carry on doing their job for many years to come. When you get it home, check all of the circuitry very carefully - it may be possible to use as-is or may require a re-build. If it's not pretty enough for you, a new front panel is cheaper than a new linear, even when professionally engraved.