Huzzah! PSK31 on my Drake 2-B

PSK31Well, after listening to one of the soldersmoke podcasts which described the old Drake 2-B as one of the premier communications receivers of all time, I began eyeing mine in a slightly different light. I’ve had this little guy in storage for eight years or so, and my experience with it was that it was pretty deaf. But I began thinking: to be fair, I’ve never used it with anything but a chunk of random wire. Might my experience be different with a more proper antenna?

Clearly a test was in order. I stopped by HRO today and picked up a simple 40m dipole. (Yes, I’m lazy, I could have built it myself). I have 50 feet of RG58 feedline from Radio Shack but couldn’t locate it, so once again, I couldn’t hook up the antenna properly. Still, I hoped it would make some difference. I unwound only one leg of the dipole, which stretched all the way across my living room. I left the other coiled behind the receiver. Hardly optimal. I hooked up a little stub of feedline that I had.

The CW band (Morse code to most of you) was alive with signals, where previously I might have had difficulty finding one. Huzzah! Clearly it was much better. I don’t know why I was surprised, but I was. But I wasn’t ready to stop then. I remember that I had a “digipup” live CD floating around. This is a distribution of Puppy Linux especially for ham radio, including the program fldigi, which can decode many of the digital modes that are active on HF. I booted my old (slightly unreliable) laptop into it, and set about looking for PSK31 signals.

PSK31 is a relatively new (< 10 year old) digital mode based upon BPSK (binary phased shift keying). It emits a sort of warbling sound, the peaks of which are separated by a mere 31 hz. It has rapidly become very popular with hams because of its ease of use, its speed, and its very narrow bandwidth.

PSK31 activity on 40m is supposed to be centered around 7.035 megahertz. I suspect that my calibration is off, because I found signals mostly near 7.050 khz on my band, but several were active. I clicked on one… and voila! Digital decoding! Click on the thumbnail at the right for a closer look. This wasn’t even the strongest signal, and I was receiving 100% copy.

I was psyched. I am psyched. I have a little PSK80 kit (a dedicated transciever for PSK31 on 80m) that I hope to get on the air soon, but this taste was fun!

Addendum: A closeup of fldigi can be seen in this picture.

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