Monday 18 October 2010

Back to the G5RV

Last weekend I knew I wasn't going to be using the g5rv, so I decided to try my multi-mode beacon into that antenna once again.

Regular readers will recall that I have installed a dedicated antenna for 30m beacon work (with the intention of leaving the main station antenna free for other uses). The dedicated beacon antenna is known to be something of a "compromise" - it is just a pair of Moonraker 30m whips mounted on one of their "dipole centres", to make what I have named the "runt dipole".

When I first set up the system, I had results slightly poorer to those achieved with the g5rv, but I was ready to accept the poorer performance in return for the ability to run other modes at the same time as the beacon (which runs 24/7).

I switched over to the g5rv on Friday 15th and was immediately rewarded by an email from David, ea1faq, telling me that he'd got a nice grab of my S/MT Hell signal...

As you see, David had captured my DFCW signal as well - in fact David has done great service to me, having also spotted the beacon's WSPR signals many times in the past. That's 3/3 modes - thanks David!

I left the beacon running to allow me to average over a full 72 hours of performance on WSPR and very soon it became clear that the performance with the g5rv was much better than before. Here's a comparison of the original averaged report rates on the g5rv (blue), the averages on the new "runt dipole" (red) and those on the recent return to the g5rv (green)...

For those of you who have not seen these averages before, I am counting the number of reports of each five-and-a-bit Joule "flash" of WSPR signal, which occur every ten minutes and averaging over several days of data. For the original g5rv data, the average runs over 13 (consecutive) days. For the new "runt dipole", the averaging extends over nearly five weeks (hence the smoother curve), whilst for the re-visit to the g5rv, there's just last weekend's three days of data averaged together.

In all cases, the beacon is running 50mW of power.

In spite of the risk of comparing Apples with Pears, I think it is fair to say that the performance with the g5rv is significantly better than it was before - and significantly better than with the "runt dipole".

As if the performance figures with WSPR weren't enough to be happy with, my email inbox this morning contained another pleasant surprise...

Colin, g6avk had posted on the KnightsQRSS list a description of an unusually strong signal...

Well this surprised me this evening, whilst working in shack #2 this huge S3-5 signal appeared on 30m, on checking my grabber in shack #1 it turns out to be Paul M0XPD.

The subject of Colin's post says it all: "Freak condx or QRO :)". I assured him that it is still the same old QRPp 50 mWatts and that the only change is the antenna. However, the great WSPR performance (compared to that achieved six weeks ago) certainly suggests that propagation has improved markedly too.

Thanks to all those who operate receiving stations for WSPR and QRSS - I'll get round to doing some Rx myself some day.

...-.- de m0xpd

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