DD5LP/P – January 15th 2020 – DL/AM-176 Rentschen – Antenna and grey line tests.


As we have had some sunspots from the new solar cycle 25 and the SFI index was up at 75, I decided to do an activation back at the just after dawn hours to coincide with the grey line and long path propagation to Australia. I wanted to see if this window was once again open to Australia as of late we’ve been using the later short path windows at around 1030-1130 UTC. The predictions were that the SFI should stay in the mid-70s for a couple of weeks.

I chose Rentschen as it is an easy access plateau type summit where I have lots of room and could put up my 40m VP2E antenna which I was still not happy was working as expected and I could also put up my 40/30/20m linked dipole so that I had a comparison. As conditions were unlikely to be “easy”, I would also take my recently purchased and boxed Chinese 70 watt HF amplifier to give the signal a kick. I considered also re-testing my new external DYC-817 dynamic speech compressor but then (correctly as it turned out) decided I would be testing too many things in one go.

So the aims were;

  1. Test if the old early morning long path/grey line window to ZL/VK was once again available as the SFI had risen.
  2. Test the VP2E against the linked dipole on 40 metres (the dipole also providing 20-metre coverage if required).
  3. Make sure the rig sounds OK, without the speech compressor in use.

 As it would be an early (8am) start, all the gear was loaded into the car the night before so that I could just get up, get ready and go.

The Activation:

As planned I was up early – and hit the road a few minutes earlier than expected. As I would be putting up two antenna systems, having some more time available before the activation time that I had alerted on SOTAWatch would be useful.

The SFI, while predicted to stay at around 75, had dropped to 71 and worse still the K index was up at 3 and hence the bands would be noisy.

I like to coordinate my activations with when Mike 2E0YYY/P goes out as he will more often than not get contacts into VK/ZL from his local summits in the North of England. Today he was going to a HEMA summit, Mow Cop which has performed very well over the last few months for him. Mike, however, was still going out for the later window, so it was quite possible that I would be packing up at the time Mike was starting up but we usually try for a contact. Mow Cop, however, has a strange “curse”, that it seems to be blocked towards southern Germany and the only way I have worked Mike from this summit is via aircraft scatter (the summit is quite close to Manchester airport and the Manchester – Helsinki flight seems to provide a nice mirror for us on 20m).

The run down to Rentschen was uneventful and I was happy to see that the field where the summit marker trig point stone is located was bathed in the early morning sunshine. That wasn’t to say that it was warm – it might have got up to 2 degrees Centigrade while I was there, mostly it was around zero.

I set up the 40m VP2E on my 10m portable mast supported in my modified surveyors’ tripod, pointing in the correct direction for VK/ZL via long path. The linked dipole, set to 20m initially, so I had the ability to switch bands quickly if needed, went onto my 6-metre pole which had its base supported by a screw-in sunshade base peg.

One of my planned actions was to test whether the early – (Grey line) connectivity was again possible given the improved conditions over the last week. I can tell you – it wasn’t! I called and called and although I got several contacts around Europe, there was nothing from further afield on 40m or 20m. Interesting on 40m was how weak Scandinavian stations were but Spanish, French and some UK stations were booming in like they were next door – so this suggests that the VP2E is indeed providing gain in the direction it is pointed while reducing signals from other directions as it should. I left it a bit too long before thinking about comparing signals between antennas (next time I need to take a simple manual antenna switch to make it easy (and quick) to compare. By the time I remembered that I wanted to compare directivity and signals, we started to have QSB affect the bands.

With the sunspots disappearing and the SFI dropping to 70 despite the fact that the predictions were for it to stay in the mid-70s, along with a CME, which probably was the reason that there was so much QSB and higher noise levels on 40m & 20m, meant that conditions were not good for me.

I did make another discovery – the bad audio which I put down to a problem in the speech processor on my last activations is actually RF getting back into the rig’s audio. It only occurs when the amplifier is on and switching off the amplifier and hence dropping from about 70 watts to 3 watts stops the “rasping” sound in the audio. I noted to investigate this further when I got home and as I was told the audio was perfectly readable at the higher power and hence higher signal level, I decided to put up with it as I could do little on the summit (see conclusions section below).

On this activation, I lasted over 3 hours in the cold which is more than previous activations.  I arrived on the summit at 0800 UTC and left at 1115 UTC one reason that I stayed so long was in the hope of making a contact with Mike 2E0YYY/P on Mow Cop. For a long time, I could hear stations working Mike but nothing from him. When I eventually heard Mike, it was after he had switched from his Antron A99 vertical to a simple inverted-v dipole. I guess this shortened the skip distance as the signals take-off angle would be higher. He was only a 3-2 signal when we managed a contact (I was 3-3 with him) and then only for a short period. In any case, the Mow Cop screen to Southern Germany still seems to be in place! I even tried swinging my dipole 90 degrees but I couldn’t tell if it made any difference as his signal had dropped back into the noise. There’s something about Mow Cop that stops it from being able to get signals down here!

I started packing up the station at 1045 UTC and found out later that Mike made contacts into VK about an hour afterwards. So it appears the short path is still working down to VK/ZL but not the early morning long path/grey line.


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  • Xiegu X108G.
  • DX-Wire 10m mast and Lambdahalbe 6m mast.
  • Portable 70w PEP HF amplifier and cables.
  • Battery box (2 x 5000maH hardcase 4S LIPOs).
  • VP2E (Vertically polarised, 2 element, 40m directional wire antenna).
  • Surveyors tripod.
  • Screw-in sun umbrella base.
  • SOTABeams Band Hopper linked dipole.
  • Thick green plastic painters sheet and an orange plastic tablecloth.
  • Smartphone with PocketRxTx App and USB cable acting as an external display to the rig.



The propagation was not as good as I had hoped for, there was a lot of QSB around that meant any antenna comparisons would not be valid. Even swinging the linked dipole around on 20m to try to get a better signal from Mike had no apparent effect but as Mike went into the noise at that point, we’ll never know if the linked dipole’s positioning was important or not

The problems of “raspy” audio when the amplifier is turned on, appears to be RF getting into the rig and as the accessory cable carrying the Tx/Rx PTT switching also has the Auxilary audio input pin wired up but going nowhere, my modification of cutting that wire in the cable near to the rig end of the cable along with adding ferrites to several of the other cables might resolve the RFI – we’ll see at the next activation. If the RFI is now stopped, I can again look at testing the external dynamic speech processor.

What is with the cell phone networks? From the Rentschen summit, I can see the cell tower but despite that, it stopped working during my activation making spotting and communicating via email, difficult to say the least. I have a SIM for each of the two major networks in Germany (Telekom and Vodafone) in my smartphone and I seem to be having issues with both networks!

73 ’til the next summit!