[amsat-bb] AO-40 reception difficulties

[Greg Dolkas <greg@xxxxxxxxxxxxxxxx>]

I've been watching all the wonderful reports of AO-40 today, and am
sad to not be one of them.

At MA 226 this morning, before dashing out of the house to work, I
made a quick check.  No signal, not even a faint buzz.  In the past
I have had a hard time hearing the satellite, only once getting 
any sort of signal loud enough to hear.  That was a couple of weeks
ago, around MA 250 I think, and I managed to copy 4 frames, all with
bad CRC.  I have also not been successful with AO-16 or UO-11.

So, what can I do better?  My setup is as follows:

Drake 2880 with crystal changed to 8302.125 khz (moves AO-40 to
middle of IF passband), Connifer preamp, and MMDS BBQ grill antenna.
60 feet of RG-6 Quad Shield cable attaches to Icom R-7000 as the
IF receiver.  Homebrew AZ/EL rotor and doppler correction driven 
by FODTrack.  The rotor has a resolution of 6 degrees Az and 10 
degrees El.  The Az calibration was set by knowing when the Sun
would be due-South.

With the converter off, I turn the volume all the way up on the 
ICOM.  Faint hiss is heard.  Turn on the Drake+preamp and the noise
level increases a little, but is not loud.  At the peak of the one
good AO-40 pass, the audio was at a good listening level (if you
like listening to 400 baud PSK) with the AF cranked all the way up.

I believe that my ICOM is a bit deaf, but that doesn't explain my 
total lack of signals on other satellites, or AO-40 this morning.

Thoughts:

  The IF coax link is absorbing too much signal.  Probably not a
  factor unless there's something wrong with it, as the loss should
  be in the 3db range.

  There's something wrong with the Drake.  Seemed to work well on
  the bench - the "diode and resistors" signal generator came
  through pretty well (audio loud, but didn't move the S-meter),
  looking at 17th harmonic of 144mhz.

  MMDS antenna problem?  The antenna, preamp, and Drake were
  purchased together new, and seemed to pick up my Microwave
  oven well, but are otherwise unproven in combat.

  Weather & Trees - about 50% of my sky view is through some oak
  trees that are just now leafing out.  I don't know if the pass
  this morning was aimed in that direction, however.  But, it was
  raining, if that's a factor.

Anything of these sound like my problem?  Other ideas?

Thanks for any help,

Greg.
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