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