First Dabble at HF Fails

In reply to MM0FMF:

Hi Andy

Thanks very much for your considered and useful reply, food for thought and some useful tips! The answer is to try a bit of experimentation, unfortunately time is at a premium presently and I’d sooner be spending what little I have operating rather than fiddling…

I’d had what I considered to be excellent results with my computer ribbon cable antennas (at least on 60m) until my Shetlands excursion, which put doubts in my mind but I’m not sure whether the distances involved were as much a factor as anything else!

40m ssb with 5W I have found to be a recipe for heartache, having spent many hours fruitlessly calling; the only QSO’s I have completed have been made by replying to high power stations calling CQ. So I too am working on regaining the CW skills - it really does work.

Have fun at Friedrichshaven, look forward to catching you on a hill or two

73 de Paul G4MD

In reply to G3CWI:
It is worthwhile to bear in mind that most sources equate the earth with ground level. In a garden this might be a fair approximation, other considerations come into play on a summit.

On a bare, rocky summit, the rock has a very low conductivity. It has also been subjected to intense frost shattering in periglacial conditions. This means that water will percolate to quite a depth before building up, in the process it will have dissolved some metallic bases and become conducting. Thus the actual conducting earth plane may be as much as several tens of metres below ground level depending on recent weather. However there may be mineralisation of the rock giving it a higher conductivity - rare, I should imagine, as mineralised rock tends to be softer and weathers away preferentially.

On a peat covered summit, the peat is quite acidic (I have measured it as acidic as 2.5 pH) and should act as a near-surface earth plane.

It is best to assume that the earth is near the surface, but a rocky summit gives you more leeway!

73

Brian G8ADD

In reply to M0DFA:

My link dipole, inverted V fashion, started out fed by RG174 - straight into the radio or ATU. At one stage I thought I was having RF feedback problems, so I replaced the feeder with fig-8 zip flex (some people say it’s impedance is close to 75 ohms) and made a 1:1 balun on a 3/4" ring.

To be honest, I haven’t noticed much difference between the two. The “RF feedback” I get reports of sporadically hasn’t been pinned down, but may well be something else. It’s not always easy to start tracking these things down when you’re out on the hills.

HF band wise - I’ve found 80m ssb can be a struggle with low power, 40m ssb is hard work mostly because of the high congestion/noise levels. 40m CW nearly always results in a small pile-up once you’re spotted. 30m CW is a bit less manic.

60m ssb or cw is a dream 95% of the time. Low noise levels, and a bunch of great folk just waiting for you to call CQ SOTA - because it’s spot frequency, there are nearly always people monitoring. Often get 59+ reports with 5W ssb. Once you’ve done on 60m, you can tell people where you’re going to QSY and they can spot you and/or follow you there. Also, experimenting will small, back-pack portable stations that can be erected and dismantled quickly, run on small batteries or solar panels and provide national communications is about as genuine a reason as you can get for having an NOV. The collective experience of SOTA operators would be a priceless asset in many excercise or emergency situations.

In the end of course, it can be great fun to try and have as many bands/modes available as possible and all part of the challenge!

Ian GW8OGI