[amsat-bb] Re: AO-51 (2158Z) Mid Atlantic pass.

[Alan P. Biddle]

Greg,

The first couple of morning NS passes yesterday, I found that everything
worked fine, though there seemed to be a bit more QSB on the audio.
Downlink signals were good, though suffering from relatively low elevation
geometry.  On the uplink, as I saw before on LU, it required power for full
quieting ranging from 80 watts out of the brick on the horizon, to what must
have been a watt at most at TCA.  There is a very detectable threshold,
unsurprisingly with FM, though things are not normally quiet enough on mode
VU to experiment and find it.  On the previous mode LU operation, I was able
to use that threshold, and of course the sparse number of operators, to net
in my uplink frequency, BTW.

Last night, I had a "down the throat" SN pass around 0110 UTC.  Signals were
excellent, and at TCA, my S-meter was absolutely pinned, even with the 10 db
attenuator switched on.  AO-51 is LOUD on mode S.  What I did find, and
N8BBQ made a similar comment, was that there was much less QSB on the
evening pass.  AOS to LOS, it was really like a terrestrial repeater.  (Plug
for SATPC32.  It handles the rapid Doppler perfectly!)  I did notice a bit
of noise, which for lack of a better term I will say sounded a bit _like_
terrestrial intermod.  It was very low level, but I want to look for that on
some future passes.  I also need to get WA4SXM's book out and look at the
antenna locations, as there is definitely a difference in performance
depending on aspect, much more so than on VU.

Alan
WA4SCA