Two Bands, Not Much Dosh.

2 metres. An interesting band. Kind of handy for satellite working, repeaters, all that jazz.  How much for a handie, Mr.? 'Oh, that'll be $150 (or, defying all known exchange mechanisms, £150 in the UK), sir.' Hmm. Typing in ebay brings up a very decent looking handie. £34.99, delivered. Does 2m and 70cm.

2 bands, £34.99.  Brilliant!

It arrives the next day. Brilliant item, made even more capable with a homebrewed tiger tail attached so it has something more like a real antenna.  Kicks into the repeaters and even does distant direct contacts no problem on 2W.  You don't generally get scintillating conversation on 2m, but all the same, it's radio...

So, instead of spending mucho $$$ on a duplex-capable handie (if such a thing really exists), to do satellite working, I just got two handies for £70 and an antenna made for another £30. Two handies and a twin-band antenna for less than a badged handie. That's my kind of amateur radio!

PSK-31 - Shoestring Style

PSK-31 is a mode that I find curiously interesting, but don't know why.

True, you sit there, largely pressing macro QSO function buttons, as does everyone else.  But it is an interesting way to communicate when you feel a bit less chatty, or shouting your callsign down the mic at 3am might just wake the kids up.

How to do PSK-31 if you have the money - and a rig with the right ports.

I wanted to have a go at this mode, but had no interface.  Worse, and as usual, I couldn't find any sense on the internet as to what interface might be available for my elderly TS-50 that - shock!  horror!  has no data port.

My colleagues in the US, bless them, applied standard SAGA generation thinking and advised me to 'purchase a newer rig, then buy a Connect-o-Tron 5000' and set the jumpers to stun.'

Hmm.  Fine if you've a public sector pension, three houses and twelve 15L cars.

But where there's no money, there's a way.  I chose to think about it, helped along by the ever-helpful video meister, Randy, K7AGE.  Here's Randy looking, as ever, a bit rabbit-in-headlights:



See, Randy's good at making things simple.  He does go on to mention, in a very democratic way, the various interfaces.  That's where I lose interest, as these simple circuits cost a lot of money, typically need a lot of twiddling before they work, and then seem not to work very well.

So, having understood how it all fits together, here is my Super-Connect-o-Tron-6000 computer to Kenwood TS-50 interface:

My precisely zero-cost PSK-31 interface.  You've probably got one, too...

Now, I can hear the purist amateur radio lifestyler out there shouting 'ha ha ha, but what about your levels, your ALC?'

Well, first you pick a quiet section of the PSK part of the band, use the thing on your shoulders to set the output levels to a pretty low figure - I chose S3 to start with on the RF meter of the rig - and invite comments on the IMD level.  Nobody complained, but eventually, I found I could go down to zero S-bars, but  showing, in my case, about 5-7W out on the ATU meter) without any problems, this equating roughly to an IMD of -20 to -30dB.

PSK-31.  All for zero dollars!

True, you have to keep an eye on the output meters and adjust the position of the mic relative to the PC's speaker, but it does work and by the end of the first day, my log book was full of successful PSK-31 contacts and no complaints.

In the end, I don't prefer PSK-31 over SSB.  It's just something else to play with and see where the signal goes.  It's too impersonal for my liking, but I will take part from time to time, happy in the sure knowledge that I can do it with no problem to others - and without having spent a single penny!

I wonder when the magazines will run an article on PSK-31 for no money?  No time soon, if their advertising concerns have anything to say about it!

Meanwhile, here's a particularly Swedish take, showing a blatant (but very healthy) disregard for taking ham radio too seriously, on shoestring PSK-31:

Antenna Restrictions? Limited Space? Try The Loft!

Pick up any book about amateur radio antennas, and it won't be long before some plucky chap (it's always a chap) starts telling the reader not to despair if your neighbours are from hell, or your back yard is the size of a packet of frozen peas.  You can, we are assured, always make use of our loft space, where dipoles down to 80m wavelength can be dog-legged into position.

Sounds great, doesn't it?  There's always a nod to the fact that an outside antenna will be much better, of course.  But just how much worse could an antenna isolated from the big world outside by a few millimetres of slate or tile actually be?  Surely, it's worth a try if total failure is the only other option.

What could be simpler? Two bits of wire and a feeder into the loft.

So, one wild, wet June morning, I set off with dipole centre, wire and some string betwixt my teeth into the loft.  Working in a loft is never comfortable, especially when it's covered in mineral wool insulation, which quickly smothers you in a fine dust of glass.  You've also a good chance of going through the ceiling, so good life and household insurances are prerequisites.  Already, the whole thing looks much less attractive.

I had a spare set of 20m dipole quarter wave legs in the junk box, and these were strung up, standing well clear of the roof timber work to avoid any flashing over and consequent fire risk.  Our 19th century rebuilt cottage is just about long enough to accommodate this dipole.  Make note that our roof covering is Welsh slate, noted elsewhere for its poor compatibility with loft antennas.

Connecting up, I thought I would probably hear quite a bit more noise, and that signals would be down by maybe 2-3 'S' points.

The reality was rather worse.  Firstly, getting the dipole to match with a reasonably competent ATU proved impossible.  OK, an ATU isn't necessary for a dipole cut properly, but going up and down to trim is a real nightmare and so it's just much simpler, especially for initial testing.  Twin wire feed would probably have managed a better match, but I didn't have any spare, so that was that.

Yes, this wire on the lawn is a big compromise but, unlike the loft dipole, will give you reasonable results.  Image: W4CNG

Not that it was worth pursuing twin feed.  The noise was not too bad, but the signal strength was pathetic.  Indeed, it was to all purposes non-existent.  The only thing I could hear was a single Italian station at S5, who would be about 59+20dB on anything else, including a simple end-fed vertical with no radials.  Indeed, I tried a horizontal end-fed coupled to a 9:1 unun in the loft, too, and although a bit better on signals and reaching a far better match, was still useless in practice.

So on that single, scientifically dubious assessment, the loft dipole - saviour, it is claimed by the books, of all antenna-restricted hams - came in at a whopping 44dB down on any bit of wire I would care to string up outside.  If you're not getting the message yet, this means that the slate-roofed loft dipole is as good as useless.  Other roofing materials seem to be less harsh on hams.

I should also mention that the same dipole has been used to great effect in an inverted vee configuration whilst portable, so there's nothing wrong with the wire itself!

My advice?  If there's any way at all you can get any sort of  non-ideal wire outside, do so.  The loft is simply useless, even from this electrically quiet, rural area.  Even a 'grasswire' antenna is infinitely better than a dipole in the loft, and is much more interesting to try and understand.  In fact, I recently tried to see if I could make use of the lead flashing on my house as an antenna, which, although very poor, was just about making it to first skip distance, so again, much, much better than the loft dipole.

All I can say about many of the books and other sources of reassurance about loft antennas that I've read can only be endlessly and mindlessly repeating what someone, somewhere once decided was worthwhile information.  In my experience, loft antennas are absolutely worthless, certainly as far as a slate covered roof is concerned.  After all, there's a reason why WW2 spies in France and elsewhere risked their very lives by stringing their antennas outside: they just didn't work inside!