Just as an update on my strange symptoms... I'm starting to think that my
diseqC switch may be a large part of my problem. I went out to my fixed Primestar dish, and even though I had it selected at the
Mercury, on a channel I was receiving strong last week, I was getting no LNBF voltage out at the dish. Confused, I came back inside to make sure I had the parameters set correctly. While standing there looking at my TV.... POP the channel came on..... strong signal ?!?!? I connected the receiver output to a TV that was out in my garage that I can hear from the dish, and turned the volume up loud. Went back outside, and started moving the dish around... no change. I completely blocked the LNBF.... it was still playing the
PBS channel (Montanna). I even disconnected the COAX.... still receiving the channel.
At this point, it became obvious that even though the Mercury was selecting the Primestar dish, that I was actually receiving signal from my 90CM dish, that I also had aimed at AMC3, and the obvious possibilities are that either the DiseqC switch is bad, or that the Mercury is not sending the proper DiseqC signals to the switch. I've going to have to first bypass the switch (in order to re-aim the Primestar dish), then I think I'm going to switch to my old Lifetime receiver, to see if IT is able to control the DiseqC switch, and if that doesn't work, I'll replace the switch (I may actually try that first).
One weird aspect of my problem, is that even when I've switched the input over to my 90CM dish, I am initially not able to get reception on the 12180V/30000 transponder, but if I switch to one of the horizontal channels, like Montanna, it pops in, and I can then switch back to the vertical transponder, and watch that for a few minutes, but it will then pop out (go from a 70% signal quality, down to zero), and the only way to get the signal back is to switch to horizontal for a while then back to the vertical channel. Really weird, and suggests that this is a voltage thing, ie the lnbf isn't getting enough voltage, and is switching polarities on it's own somehow. That's another thing I need to do, ie monitor the lnbf voltage out at the dish, while this is happening. With a foot of snow out at the dishes though, it isn't a particularly good time to be doing a lot of experimentation.
But bottom line is that I'm not sure whether the problem is with my Mercury, the motor, coax, or the switch, but the switch is certainly part of the problem.