The aridity of 2m

When you're a data aficionado who doesn't own a mic, 2m can be a bit of a desert. We propeller-heads inhabit the bottom 500KHz or so of this band. In the wilds of the borders, this can be a long and lonely existence, punctuated only by SOTA calling from the local hilltops

Anyway, to cut a long and common story short, Santa bought me a 6m portable mast for Christmas. The aged Sandpiper 3 element delta beam sits beautifully on it, and I made up a westflex cable some time ago for 23cms (currently no antenna...)

So, it all fits together. What to listen for? There was the excitement of the Quadrantids. I capured these on a collinear:

160200 13.6 4230 12 37 -197 EA3AXV CQ EA3AXV CQ EA3AXV CQ EA3AXV C


And, a little later,

232400 14.4 400 10 26 -20 S!CQ 352 OK2PMS CQ 352 OK2PMS CQ 352 OK2


Both of which are quite gratifying on simple kit. No chance of replying, of course.

Anyway, back to the beamlet. It's been pointing towards London today. Been trawling down in the 144.135 ish region with PSK31 - no takers there, nor, indeed, anything on JT65B which is, if you read the internet, flavour of the month digitally for 2m - though I suspect all the activitiy occurs either as EME or during openings

But I did manage to pick up GB3VHF. This is located SE of London and, rather sweetly, beacons in JT65B if you set your QRG to 144.42850 USB. Today, in Shropshire, this has been a lovely -6dB, easily audible and well above the noise floor

So, still no QSOs, but at least I know I can reach to Kent.

I did try F5ZAM after that. It's a 10W beacon, probably CW, on 144.425. Pas un saucisson on that one...

The mysteries of propagation

G4VXE and I had another little play on 2m JT65. Same QRG (144.165.000 if you're interested in joining us), same kit, same antenna, just 24 hours different.

Completely different ballgame. We had to go up to 20W, and only just completed.

It confirms what we all know, of course: that when bands are open, you need no power. When they're shut, you need lots of power and it's still difficult- these two occasions were more than 22dB different! You can't make that up with a linear. Even a linear AND a beam. The interesting thing is what's different about the two times. I don't think last night's "opening" was forecast by anyone or anything, and the band wasn't crowded with DX chasers.

We followed this up with a short burst of JT9-2. Clearly, JT9-2 wasn't designed for a closed VHF band, but there seemed little point in trying JT9-1, with essentially the same "floor" as JT65. Anyway, it was a spectacular failure, despite being able to see the other trace on screen and, in G4VXE's case, measure it as -22 - well useable.

We put the failure down to version incompatibility - I was on v0.3, he was on 0.2

VHF JT65

Tim, G4VXE, and I had a short session this afternoon with JT65 on 2m, using the JT65-HF program, just because we both had it configured.

We started out on 144.165.000 using 10W each, into a collinear at each end. My collinear, just so you get the picture, is screwed to a shed wall. I can touch the bottom of it. The copy was, by HF standards, astoundingly easy - we exchanged -05 (him at my end) and -09. Tim dropped to 1W, and I still had very easy copy at this end, well above the noise floor.

A back of an envelope calculation suggested that we'd hit -24dB at 150mW. This is over 140 km, with "poor" aerials. I can't get that low with any of my kit - pout!

There is a lot of mileage to JT65 and its siblings on VHF. I'd like to try this on 23cm

VHF WSPR

During that interlude of "poor" propagation yesterday I decided to have a go at setting WSPR up on 2m.

The tricky bit was finding the agreed frequency. After a bit of searching, 144.489.000 seemed to be the agreed one (WSPR itself told me a dial of 144.488.000....)

Set it up and left it, and was very pleased to see G4VXE pop up, both ways

The intriguing thing here is that if you look at his screenshot of the same QSO here, you'll see that I am at the top of his passband, whereas Tim is at the bottom of mine. Somewhere or other, there's a discrepancy of around 100Hz (I was TXing around 500). I suppose that's not too bad for uncalibrated rigs at VHF, but it is a bit disconcerting. Mine is an almost new TS-2000. Wonder what Tim was using?

I will certainly be on 144.489 dial using WSPR again. Will you join me?