Monday, September 14, 2009

APRS DX

Sunday was a fine day - though there was a bit of a cold breeze from the east - and my wife Olga and I decided to take a picnic lunch and my VX-8E for a stroll to the top of Ling Fell, one of the lower Lake District hills that is 205th in height seniority out of the 214 Wainwrights.

I only made two contacts on 2m FM using 5W to a Comet SMA-24 antenna. The first was with Gordon, G0EWN/P who was on the summit of Skiddaw in clear sight of me (the summit, not Gordon!) I couldn't raise anyone else after that so we had lunch and then I called CQ again, to raise Tony G1OAE in Workington.

Although Ling Fell is not all that high - about 375m according to the GPS in the VX-8E - I could hear on 144.8MHz the frequent "brrrap" sounds of APRS signals which I never hear at my home station. Most of them were too noisy to copy, but the VX-8E decoded a position report from EI2MLP at a distance of 319km, which I later found was on the summit of Leinster in south east Ireland. I also received a status report from MB7UND apparently in Taunton, Somerset, listing EI5GRB as DX heard. So clearly there was some tropo about.

Obviously a better antenna would have helped to make more contacts, and dedicated Summits On The Air (SOTA) activators would probably say that it is a waste of time going up a hill without one. However, my objective is primarily to have a nice walk and a picnic lunch with a nice view, unencumbered with kilos of aluminium. I also feel that it is wrong to spoil other people's enjoyment of the summit they've spent time and energy to get to by erecting antennas. Even this minor summit had half a dozen visitors in the hour or so we were up there. How people get away with putting up beams and HF dipoles on the more well-known and popular tops I can't imagine. I guess you need a thick skin and a willingness to ignore adverse comments.

Receiving these DX APRS packets made me think that APRS could be a useful tool to detect openings on 2 metres. It's too late for the Sporadic-E this year, but I'd be interested to hear from anyone who has used APRS as a propagation detector.

4 comments:

David said...

Where I live in the US in Northern NJ, there are dozens and dozens of APRS messages coming in every min so it probably wouldn't help much unless you were able to set a distance limit, but the distance limits I've seen on a HT are more with discarding those outside of a range vs only allowing those outside a range to be processed.

Just what my experience has been though maybe it's different in your part of the world.

73,
K2DSL - David

g4ilo said...

Where I live there is hardly any APRS activity at all, so any increase in the number of stations heard would have to be down to lift conditions. From the locations of the stations heard you could determine the direction of the enhanced propagation.

Never having experienced levels of activity as you describe it, it never occurred to me that my idea would be impractical for most people. Thanks for the comment.

Steve Bunting said...

Hi Julian - it as already been done:

http://www.mountainlake.k12.mn.us/ham/aprs/path.cgi?map=eu

g4ilo said...

That's amazing, Steve. I'll definitely be bookmarking that.

Funnily enough, I was thinking about whether that could be done on the way back from my walk. But I thought it would be impossible to exclude HF reports or distinguish 2m from 70cm activity.