2008-01-20
HAARP/LWA EME Listening
HAARP and LWA conducted a similar experiment back in October. I only wish I had heard about the latest tests with enough advanced warning get a good setup prepared. I saw discussions on QRP-L on the 19th about 2 hours *after* the first test was over!
Anyway, I managed to throw together a primitive setup to hear the signal. A quick play with Stellarium told me the moon would rise before the experiment would finish, but would be very low on the horizon during the tests. I figured I'd have a very hard time hearing echoes, but with the multi-megawatt CW power of HAARP's transmitters I stood a good chance of hearing skywave signals. I strung an end-fed half-wave antenna in a sloper configuration off the balcony, a bit off north-south so it would be broadside to the arc the moon would trace during the experiment.
The only radio I had available was my VR-500, which is pathetic at HF. Its poor selectivity may be why I failed to hear the first hour's transmission, although I was being QRMed very badly by some other transmissions. I also had to use it with the attenuator in to prevent overload.
During the last half hour I clearly heard a CW signal being keyed on 2 seconds, off three. Here is the spectrogram of the last 200 seconds I recorded. The signal stopped right on 0830Z, so I am pretty confident it was actually HAARP I was hearing.
You can listen to this recording here in MP3 Format.
I have no idea if I was hearing Luna echoes or the skywave signal, but I definitely wasn't hearing both. It seems quite unlikely that I was hearing Luna echoes, it is more likely the direct skywave signal I was copying. Although I did hear a few moments where there was a signal in-between the 2 second pulses, somewhat higher in frequency and only half-second pulses. I haven't done the Doppler math to see what frequency I should have expected, I assume these offset tones are QRM or timing signals from HAARP itself?
Here is the audio corresponding to this spectrogram in MP3 format.
I wanted to setup properly with a receiver for a time reference, fed into one channel of the recording and the HAARP signal into the other. Unfortunately because of the rush I only had my laptop with its mono microphone input to use as a recorder. In fact I ended up using sndrec32.exe for data capture, that's how badly I was prepared!
Next time (and I hope there will be a next time!) I'll have a real narrow band HF receiver feeding a PC running baudline and a time reference being co-recorded. This experience has rekindled my interest in propagation research. I have always wanted to build a small listening station, with a fluxgate magnetometer, LF beacon receiver, etc. Like so many things, it is just a matter of finding the time to build it.
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