One of my non-contest activities has been hanging out on six meters.
As it turns out, it is possible for a single yagi station on six
meters (albeit a pretty big yagi) to hear signals off the moon.
Recently, while trying to work a station on the east coast (WA4NJP),
I made a recording of a moon echo that has had some interesting
results. If I play this recording here at work - most people
can't hear the echo. However, most of the contesters I play it
for can hear the echo. Obviously, those who have spent a lot of
time listening to weak CW signals have developed better "DSPs"
inside their brain.
I thought I would let y'all have a crack at it and see what you
think. Perhaps this is one of the many skills that the successful
contester needs to develop.
You can hear the 4 second sound clip at
http://www.kkn.net/~tree/ratrat.wav. You will hear RAT sent
followed by the echo off the moon. I think it is best if you can
listen with headphones at a LOW volume. It seems that the ear
has an easier time with it then. You might also just want to listen
to the second half a few times to pick the echo out.
It might also be interesting to note that the bandwidth used in
the receiver is 2.7 kHz. I find this filter setting to be more
effective for EME signals than the narrow settings. This might
seem counter-intuitive. Not everyone agrees with this technique,
but many do. It seems that the brain has an easier time picking
out a weak signal if there is a wide band of noise for it to
compare against. There probalby are some experts out there who
can explain this better than I can.
This echo was recorded with the moon around 8 degrees of elevation
using a 7 element yagion a 37 foot boom at 45 feet. The transmitter
output was 1500 watts.
You can hear some other sounds at my six meter EME page at
73 Tree N6TR / K7RAT
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