This is my newest radio. It's called a Pixie II. It also happens to be the first amateur-band transmitter I've ever made.

These things are pretty cool. It is a continuous wave (CW) (or morse code) transceiver operating at a fixed frequency determined by a crystal on an HF band. Mine's configured for 80 metres using a 3.579545 MHz colorburst crystal. To move it to another band you just need to change the crystal and the L and C parameters of the antenna pi network.

The associated circuit description claims that it puts out a couple of hundred milliwatts. I'm not sure exactly how much power it does produce as it doesn't move the needles on my SWR meter but I intend to do the theoretical analysis sometime.

So what is it? Refer to the schematic. It's a Colpitts crystal oscillator running permanently at the transmission frequency. When the morse key is closed this pulls down the emitter of Q2, allowing it to amplify the oscillator into the antenna. When the switch is open the received AC is multiplied by the local oscillation frequency (direct conversion) and the result is superimposed on the supply voltage and applied as the input to an LM386 amplifier. This amplifier then provides a fixed (!) gain of 200 to the multiplied signal and in my case is attached to a 1 W 8 Ω speaker.

Despite the simplicity of the circuit I'm pleased to say that it really does work. I've tested both transmission and reception with my much fuller-featured Yaesu FT-7B.

There are a few bits missing, which is very much the point. The intention of the Pixie II is to provide the basic operating radio so that the operator can make improvements. In this case I would like to add a proper audio power amplifier with volume control, an automatic gain control for the received signal and some tuning capacitance. I'll need to take some measurements but I'm hoping I can get a stable 20 kHz tuning range with appropriate loading capacitance on the crystal. I could also experiment with an antenna filter with a sharper roll-off.

When I make these improvements, coupled with a decent antenna there's no reason why I couldn't have proper QSOs with this radio or even run it in a contest. Being low power and on 80 metres, it is not going to get much more range than Tasmania unless we get some crazy sun spots so I'm hoping that I'll be able to find some other morse operators within the state. If you're a radio amateur you should build one of these.

Perhaps I should learn morse code too.

Yes indeedy. So far it hasn't broken. Reception on 80m isn't awesome but that's probably because it's more of a 10m or 20m dipole and that it's still not all that high. It may come down when it rains or when the wind blows around the branch to which it's attached. Not shown in the above diagram is the 10 loops of coax which form the air-core balun.

Sometime I'll make one properly. Honest. But for the meantime, I'm on HF again! \o/

It started with a beautiful Saturday. The weather in Hobart was nicer than it has been for months and refusing to stay inside, I went outside to play with antennas. I wasn't certain about the health of my HF dipole, which is constructed largely from a broomstick and gaffer tape, so I took it down for a little TLC.

Some conductivity checks showed that there were still good connections to both of the legs of about 12 metres of 12 gauge, and a short hadn't developed either. Excellent. I put it back up, running the wire into a tree on one side and over some balcony on the other so that it was a bit higher than before. Unfortunately it was running against some metal structure, but when I fired it up it tuned up fine with the tuner and I was receiving VK2, VK3 and VK4 stations fine.

It was about 2PM by now, and listening to the lighthouse stations on 40m I heard mention of the RD Contest. I panicked briefly and checked the date---oops, it was starting in a few hours. I still hadn't learned CW as I'd hoped I would by this point, but I continued to monitor HF until I had the disconcerting experience of the noise floor dropping by about 20dB suddenly.

I wandered outside and sure enough the tree-tied half of my antenna had become well-grounded. By, er, falling onto the ground.

Oops. Something to work on when the weather improves. I plan to make a more solid mounting platform for both the dipole wires and the coax feed with some strain relief. Rather than, say, nails and tape.

I went on to participate in the contest using 2m and 70cm with my Yaesu VX-6R HT attached alternately to the 70cm yagi and 2m 5/8 vertical visible in the above picture.

Sadly it was fairly quiet on VHF this year. Overall I heard only 10 or so southern VK7 VHF stations, and through less than stellar effort I managed to make 54 contacts over the 24 hours. Those who pulled all nighters such as Danny VK7HDM and Justin VK7TW made approximately 160. With the low number of participating stations the spread of contacts was determined by how late you were willing to stay up and whether you had the hardware to manage all the different modes and bands. (I didn't hear about anyone doing CW, though I'd be willing to give it a shot with an appropriate rig.)

There may not have been many people, but it was fun all the same. I had some good chats with people I hadn't spoken to for a while between the not-so-frenzied number swapping. We agreed that we definitely need to get some F-calls in on the excitement for next year.

As for the commemorative side of the contest---remembering the radio operators who died serving in wartime---lest we forget.