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...

JT65 encapsulated

JT65 transmissions in the 30m band plotted in three dimensions. To the right is time, to the left is frequency and up is "energy"

I do like representations like this.

Plotted with speclab - which is wonderful. And free.

Using WSPR

I thought I'd try using WSPR to work out where to expend my loggable efforts this morning (the WX being fit for nothing else)

Five minutes on WSPRnet maps followed by a quick hour on 40m WSPR convinced me that 40m was a band worth trying. Here is the result of an hour or so this morning, on the 817 at 1W to a LW:

So, I get the better rig out, power about 20W, tune to 7.039MHz (I looked it up on http://hflink.com/jt65/ - I don't often try 40m JT65) and set up a JT65 CQ. Twenty minutes later, I have heard absolutely nothing. Eventually, I fetch up the PSKReporter map and discover three monitors on 40m, but they are all on 7.076MHz.

My bandplan says 7.076 is all modes but excludes digimodes.

Confused.

Anyway, I migrate up to 7.076 and, of course, it's knee deep in SSB. I've got one decode, but I can't see anything clear to TX into.

40m is a mess!

DX-ing

One of the more annoying features of propagation is that our signals get weaker the further they travel. This adds to the general frisson of working DX and nowhere is this more apparent than with JT65 and the "weak" modes.

Let's talk hypothetically. I see a nice tasty piece of DX pop up on the decode list - let's say it's Hawaii or somewhere quite difficult to get from the UK. I'm running about 10W which, as far as I am concerned is about the reasonable limit (I might occasionally go up to 20W on 160m when it's silent and I know I am not getting out). What almost invariably happens is that a station nearer to the "dx" will call at the same time, and our friend only gets one decode - the stronger one. So I wait till next time. And so on

This makes working pile-ups in JT65 (an odd concept, I know, but it does happen) almost impossible. I've watched one or two and, what happens often is an arms race. The combatants are blissfully unaware of each others existence. All they know is that they are on frequency and the guy isn't responding. So it's a little tweak on the power. After two or three goes the power is quite clearly, shall we say, large, and neither party has got through. Progress is only made when one of the pair gives up.

Compare this with CW, where one can work split, and the callers can (and do...) smear out along a portion of spectrum so that the DX can pick them off one by one.

Now I have a low boredom threshold. I listen to CW pileups and maybe have a halfhearted go, but I don't stand much chance with 50W and a LW. I *can* work DX in JT65, but it's frustrating because there are unscrupulous players with large power knobs.

So, make it your New Year Resolution to support the DX Code of Conduct

The DX Code of Conduct

And, if you want a sad and slightly different tale, try reading Randy Johnson's piece here

JT9-1 success

I downloaded v0.5 of the JT9-1 experience from Joe Taylor's Website - you want WSJT-X - and it's a MUCH better experience. It all seems to work nicely.

I've tried it relatively low power (around 10W) on 160 metres, and have worked my way up to middle europe on it. The QSOs are reliable, it tunes well, and it's acquired some of the enhancements that HT65-HF has - the red and green bars, the click to continue the QSO. And it is MUCH more spectrum frugal than JT65 - and yes, it even gives positive reports sometimes

All good. I look forward to working you :-)

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

"poor"

The propagation tools all describe band conditions today as "poor", and most people seem to have taken heed and disappeared to polish their antennas, or some other diversionary activity.

I turned WSPR on, on 40 metres, and picked up a couple of stations running 50 mW beacons - DL1FX and EA6FG, both pretty regularly throughout the afternoon.

I often intend to drop power but forget - once one beacon has gone off at 2.5W (my normal power) there's no real point in dropping it. Dropping the 817 to 500mW will have to happen soon, just to see what 500mW and a bit of wire in a gutter can really do!

JT65 on 20 metres was eerily quiet. But through the murk, a Taiwanese station closing with a Thai station, then a BX (mainland China) working someone else. I guess this DX would normally be drowned out by the cacophony of QRO European operations. I didn't manage to work them, but was pleased to see them

On a slightly different tack, I worked someone on JT9-1 last night. The conversation went thus at the start:

CQ M0DEV IO82
M0DEV G1AAA XX00 (I've changed the callsign)
G1AAA M0DEV -07
M0DEV G1AAA -10
Now ok, he's missed acknowledging my report, but he's sent a report. Maybe he just clicked the wrong text to send.

G1AAA M0DEV RRR
MY REPORT PSE?
What? Sorry?

I sent the report several times, and the reply was REPORT PSE
and finally RRRRR 73 73


So, I think we're in the bag. An email arrived from him this morning to ask why I never sent a report. He claims I was sending "G1AAA M0DEV"...with no digits on the end.

If you can work out how that happened, I'd love to hear it.

The exchange also underlines the importance of sticking exactly to the agreed protocol when we can't have a proper conversation. If he didn't get my original report, he should have pushed on with

M0DEV G1AAA XX00
until he got it.

The Bear Garden: 20m JT65

I've continued to play with QRP on digital modes, and elected to try 20 metres JT65 this morning, whilst it was fairly quiet. Bear in mind this is QRP not qrp - I am using a piece of wire draped over a drainpipe, not low power to a beam antenna

Here's the picture after fifteen minutes of operating at 2.5W on the 817 - so about 2W, by the time it reaches the drainpipe.

- which is encouraging!

My 2.5W has made it to North and South America, Japan and most of Europe.

Completing a QSO was a little more involved - there was a QRO RTTY station right in the middle of the range of 14.076. I remembered that my 817 has a Collins filter for CW in which, fortuitously, works in DIG mode and, fortuitously, is almost exactly the right width for a JT65 signal to fit in it. Pop the NAR button, TX, and RU3VQ, just under 3000km away, completed with me. That, because of domestic issues, is the end of this morning's experiment.

JT65- the appeal

I've been trying to think what appeals to me about JT65. It's an odd mode to use - you're restricted to a formulaic exchange of position, signal reports and that's it. And a full QSO takes 7 (seven) minutes. PSK31 is positively sprinty after an hour of JT65. PSK31 got me back into radio about ten years ago. I blow hot and cold, and the really narrow bandwidth of PSK31, the technical appeal of the whole thing got me going again. I even sat down and learned CW to get onto HF (I was a G7 at the time - VHF only). But the rubber stamp QSOs - inevitable when I suspect most amateurs cannot type, and the inevitable RSQ 599 reports are irritating. So, PSK31 got me onto HF, and I migrated to CW. But JT65 has a number of appeals over CW and PSK. Firstly, the signal reports are genuine. You know you're being a LID (-03) or using your power justifiably (-24), and can adjust accordingly. You realise how fickle propagation is when you get a -03 from Italy, and a -20 from south east France five minutes later. Or how directional your antenna is, or how variable other amateur's rx performance is.....

The other really neat thing is that you can see, using pskreporter and to a certain extent, the RB (Reverse Beacon network), how successful you are being, even if no-one is prepared to talk to a lowly, common as muck M0.

So I keep coming back to it. I can work DX using 10W off a low LW hidden in the trees at the side of my garden. I can't do that in CW or PSK as easily.