I took the battery out of the clock / weather station to silence its interference and went down to the bottom of the garden with the home made antenna and the FT-817. I couldn't see the moon this evening as it was cloudy - in fact, attempting to drizzle - but I pointed the beam in the same general direction as last time, turned it vertical to minimize the QRN and started tuning around 432.045MHz. After a minute or so I heard some weak CW.
If I had to give a signal report it would have been 319, the signal was about equal to the noise. Sometimes it would pop up a few dB above the noise for a second or two, and I heard the call KP4AO (though not all in one go), reports being sent, R, 73 and BK, but I couldn't make out any other calls.
I had the computer interface plugged in to the FT-817 so I brought down the Samsung NC10 netbook which I have been using for my Echolink node and tried to make recordings of what I heard using Sound Recorder in order to listen to them again and even put some samples here. But for some reason when I played them back on my shack PC all I could hear was noise - the CW had all but disappeared. What a disappointment, to have no record of this rare event.
Then, on a sudden stroke of inspiration, I changed my computer sound card settings so that I was using the Realtek internal sound card - normally used for HF digital modes - to play back the audio in place of the cheap USB "dongle" I normally use for computer sound. What a difference! Instead of just hiss with a barely detectable hint that a CW signal might have been there, I now heard the KP4AO signal via the moon just as I heard it live off-air. I have converted a couple of samples to MP3 format without much loss of fidelity so you can hear for yourself what I heard:
- Here is a short sound clip from KP4AO recorded at 1937 UTC
- And here is a slightly longer one recorded around 1945 UTC
An interesting evening's experiment. Not just because I heard signals bounced off the moon for the first time ever but also for the unexpected demonstration of how weak signals get lost when you use a cheap sound card. I had been planning on using one of those USB dongles to make my own SignalLink interface. I think it's back to the drawing board on that one.