Arecibo success

This evening I managed to hear signals bounced off the moon using an FT-817 and an antenna made from a stick and a few bits of wire.

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

The CW certainly is weak but you can pick out letters now and again. If you manage to pick any calls out of those samples then you have better ears than me (which is certainly possible.)

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.

EME with a handheld

This morning I made a 6 element Yagi for 70cm using some 25A copper mains wire with the insulation stripped off and a length of wooden dowel. I copied the design from CT2GQV's blog. The object is to see if I can hear radio signals bounced off the moon.

If you didn't know, a bunch of guys that include Joe Taylor K1JT of WSPR fame have got permission to use the 1000-foot dish of the Arecibo Radio Telescope (shown above) for a couple of hours each day over this weekend to make radio contacts via EME. Using full power their signals should be strong enough to be heard using a hand held yagi and it should be possible to work them using just 100W with the same antenna.

I only have the FT-817 with 5W so it isn't possible to try to work them, but I thought I would try to hear them, which is why I made the antenna. I think you'll agree that their antenna is more impressive than mine! There are, of course, no 70cm signals to test it on, but there are plenty of noises and the yagi seems quite directional. The SWR is about 1.7:1 at 432MHz and falls gently as you go lower in frequency, but I'm not sure how to adjust it so I'll leave it as it is for the moment.

The first session was yesterday. Unfortunately their PA blew up so they were only able to run 25W of power. Some contacts were made, but obviously not with people using low power and hand held antennas. Hopefully they will have got a PA working in time for the remaining two sessions, otherwise I am not going to hear a thing.

This evening they should be on between 1740 and 2020 UTC - that's 1840 to 2120 BST. They will be transmitting on 432.045MHz using SSB or CW. Their call is KP4AO. The moon is only showing quite a thin crescent at the moment so it may not be easy to spot during daylight, even assuming the sky is clear as it is here. If you are in the UK the moon will be at an elevation of about 45 degrees to the south-west at the start of the session, declining to about 25 degrees due west by the end of it. If your QTH is elsewhere you can use this web site to locate it.

Tomorrow's session is scheduled for 1840 to 2125 UTC - 1940 to 2225 BST. The moon will be in the same position relative to the start of the session.

Fingers crossed that they get the PA going so we can have a chance to hear something. If not, the antenna won't be wasted as I've been meaning to have a try at satellite communications.