DD5LP/P – April 21st. 2016 – DL/AM-176 Rentschen.


As part of my attempt to get a station together that could operate on 80m from a SOTA summit. I had built a drastically shortened 80m dipole by including coils in its length. This was created at home based to a similar design that I have already installed at the home QTH only without a balun and of lighter materials but of course until I tested it out in the open on a summit, I did not know whether it really works or not. The problem with portable antennas for 80m is their size and very few summits have the space to put up a full sized 80m dipole, so a smaller antenna was needed. I had originally intended going to Ammerleite however Rentschen gives a lot more space and the distance from the car to the summit is a lot less, allowing me to pack more test equipment in the car in case I needed it. My wife also agreed to come along and as we then take our dog, Rentschen was a better choice. It also would earn me 1 activator point as the last time I activated it was in 2015 whereas Ammerleite would not.

I had also expanded my Ramsey QAMP to operate between 80m and 15m using switched low pass filters in its output and while this had been tested on the bench, it had also not been tested in the field with the changes. As I did not expect many contacts on 80m, I decided running 30w from the amplifier rather thn just the 5w from the FT817 might be essential, so the QAMP would be taken long.

The Location:

Rentschen is about 45 minutes drive from my home. A drive I had done several times before and so no maps or navigation equipment was needed to get to site. Rentschen is a large grassed plateau sitting above the surrounding area. The actual summit is marked by a small trig-point stone, where there is also a small post, which while fimsey, can act as a mast support. The summit location is only about a 100 metres from the road, where I parked the car.

The Activation:

Once I had put the new antenna up, and laid out and connected the rig and amplifier, I took a tune around 80m and hearing nothing I went bck to my alerted operating frequency, 3670 KHz and started calling CQ SOTA while also sending a spot. I don’t know why but cell phone coverge from this summit was marginal and I had to place my phone in a particular position before it would send and receive SOTA spot data. This was actually 30 minutes ahead of my planned activation time, but after a couple of calls I heard a very faint signal, it was Herbert OE9HRV but why was he so weak? I thought I might have a cable break, so I disconnected the amplifier and connected the new antenna directly into the FT817 and then Herbert was full strength, so I tried calling him just with the 5w from the FT817 but it seems he had given up by this point. I got a report from Mike G6TUH that he had heard me at 5-3 but then I droped into the noise. I suppose this might have been first of all the 30w and then dropping to 5w but at that time of day a signal on 80m shouldn’t be able to get to the UK, about 500Km is the normal limit, which is mid France from where I was located. In any case, something was wrong with the amplifier. On receive the antenna connection should switch straight through, so the new low pass filters couldn’t be the problem, but a broken internal cable could be. In any case it was not something I could find and fix while out portable, so unfortunately the 80m antenna test was inconclusive and I’ll have to try again on another day. So down came the 80m antenna and up went the Aerial-51 OCF dipole and I ran off a few contacts on 40m to qualify the summit, so the afternoon was not a total waste of time. In fact it wasn’t anyway as it had been a nice sunny, warm, but not too warm, afternoon out.


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Yaesu FT817ND.

Drastically shortened 80m dipole.

Spiderbeam Aerial-51 UL-404 off centre fed dipole.

5 metre squid pole.

Ramsey QAMP 80 through 15m amplifier and batteries


Activator Log


Although the test was inconclusive, the fact that a signal was received into the UK, looks hopeful.

I fell fowl of the problem of changing two items at the same time. The QAMP must have a strange problem specific to the 80m wiring as it worked OK on 40m. Perhaps on my next test, I should simply try with just the FT-817 and if that works fine, then added the repaired amplifier into the circuit?

73 ’til the next Summit!