De G4YSS, 23-05-07.
Following the polite enquiry, sensitively relayed to us via Richard G3CWI and the ensuing discussion about the 80m channel of 3.725 MHz, the use of which, it seems I have the (now) dubious pleasure of pioneering for SOTA ops, I should respond.
I can sympathise with the net in question but like others have correctly stated, no frequency has a ‘name written on it’ and there may not be a single channel on the whole of the 80m band to which someone might lay claim for one reason or the other. The salient point to this is the initial checking of occupancy, something all other SOTA activators, and I must habitually do. This is done whatever mode is to be used and I first ‘listen wide’ if CW is to be used. As can happen on 80m, the band may appear full but if the activation is to take place, some channel must be found. If 3.725 is clear, it will get used by SOTA, because if SOTA doesn’t use it (and the net is not running at the time) someone else certainly will. If it’s busy, the QRG could be 3.728, 3.722 or as far away as 3.712 etc but skilled chasers will always find the activator. My rule of thumb for SSB is to look for a 3kHz ‘gap’ to fit into but it’s often very difficult.
The initial reaction was to try using another frequency but I fear it would only be a matter of time before that too would prove unsuitable for similar or unforeseen reasons. Basically 3.725 and every other channel on 80m (or 40m) is at times close to being ‘unsuitable for communications’ simply because we are all competing for finite band-space and there will inevitably be conflicts and frictions such as splash-over, strong stations ‘wiping out’ weak etc. Tensions are raised.
Having said that, a better frequency might be found, which could eventually become a recognised SOTA channel. I know that 3.666 is regularly used but maybe sometimes that is occupied etc. Finding a regular ‘slot’ would take a great deal of painstaking research, an intimate knowledge of the entire band on a 24/365/eleven year cycle basis and it still wouldn’t satisfy the requirements of two coincident SOTA activations. I don’t know of a document which has a comprehensive listing of all or any of these net / specialised use frequencies, so we only have a band plan to go by. It states that we can use CW, SSB or any other mode (2.7kHz or less width) from 3.6 to 3.8 (so long as we have a current and correct licence, of course.)
History: The (SOTA/G4YSS) use of 3.725. It was first used by G4YSS/GX0OOO/P on 30 May 2004, for an overnight summit-camp at a time when 80m was not supporting daylight propagation. Why 3.725? It is simply the frequency, chosen for (no particular reason except perhaps easy remembering) which has been used by the Scarborough Special Events Group (GX0OOO) for all its GB-call operations, several times a year, in sunspot-low, since 1987. Since 2004 and up to 15 March 2007, it has also carried over 1200 of my SSEG SOTA QSO’s. Apart from being ‘wiped off’ in mid activation on two occasions, I can’t remember there being any problems.
Two-mode operations were introduced as an experiment from Cross Fell on 09-Nov-06. This trial was successful and regular CW/SSB activations took place on there throughout the winter of 2006/07.
Why dual-mode/single QRG?
- The antenna length, so important for SOTA, is more favourable than for the CW-only section and no re-tuning is required.
- It’s easier for the chaser. SSB chasers can tune-in during CW ops, without fear of losing their ‘quarry’ after a messy QSY.
- Chasing with SSB is far more difficult in poor condx. but the chances of success can be judged by the strength of the CW signals.
- It’s easier for the activator, he only has to assess whether the increased bandwidth will fit in, rather than start at square-one, finding an entirely new channel, remote from the first. As prevoiusly stated, this is not an invention of mine. WAB have been doing it successfully for the past 3 decades.
A CW practice net has been heard on 3.725, early on some mornings. It’s not clear which mode is causing the most problem to the net?
The bottom line: I may well continue to use frequencies in this general proximity, bearing in mind that 3.724 (3725 minus 3) may now be more appropriate, until a better (proven) alternative becomes available. I will be extra vigilant in checking the frequency (and 3.727) especially at the times given and will continue with my past policy of politeness and tolerance. Should any conflict arise, I (like Frank G3RMD) would be quite likely to ‘give-way’ whether in the wrong or even in the right, in the interests of good relations with other groups. My apologies to Frank; I feel some responsibility here.
Fritz say’s, ‘Keep cool.’ Excellent advice!
Finally, does anyone know (for certain) of a frequency where a net or other ‘claim’ is NOT operative?
73, John G4YSS (and on behalf of SSEG.)