? AMC3 weirdness ?

wejones · #1 (**permalink**) 12-01-2007, 04:53 PM

Did anyone happen to be watching PBS on AMC3 today? This morning, and early this afternoon, I had my fixed Primestar dish tuned in to one of the AMC3 PBS channels (12180/30000), and was getting a good signal. I went out to a store for an hour or so, and when I came back it said "No Signal" Changed channels (although on same transponder), and nothing. Didn't think to change transponders. I decided to switch to my motorized 90CM. It was also aimed at AMC3, and it said No Signal too!?!? I told that dish to go to a channel on AMC5 (NYN). It did, and the channel came in fine. Went back to AMC3...... NOTHING. No Signal. So I decided to try by BUD, which was on the other end of the arc. Told it to go to AMC3. Took a couple minutes to get there, but when it did, PBS was coming in strong as I've ever seen it. So I went back to the 90 CM.... channel coming in strong as ever (I hadn't touched it from when it was saying no signal). So I tried the fixed Primestar again..... Nice strong signal.
All I can say is WEIRD. Only thing I can think of, other than the transponder going down, is that maybe the DiseqC switch was acting up.
Anyway, did anyone happen to be watching PBS at around 2:30-3:15 EST? Ie I first noticed no signal at around 2:30, and I got the signal again at 3:15.

Probably my switch.

Jim-S · #2 (**permalink**) 12-02-2007, 09:04 AM

Hi wejones, I did experence the same problem. As you know I am having trouble with my system but it was working for a while yesterday and I too noticed that AMC3 was not there, I thought it was my system but I could get the other sat's just fine. I had notice this once before a few days ago but again I thought it was my system. ???????????
Jim-s

wejones · #3 (**permalink**) 12-02-2007, 10:35 AM

Quote:

Originally Posted by Jim-S

Hi wejones, I did experence the same problem. As you know I am having trouble with my system but it was working for a while yesterday and I too noticed that AMC3 was not there, I thought it was my system but I could get the other sat's just fine. I had notice this once before a few days ago but again I thought it was my system. ???????????
Jim-s

Thanks for the additional data point. Strange. Usually things like this ARE some problem with the home setup, and since no-one else seems to have noticed the problem this one probably is too. But this was a strange one for me, since PBS was GONE, then it basically came back on it's own, on two different dishes, without any changes on my part.

The one thing that came to my mind though was that at least for me, it was very cold (for this time of year) yesterday, I think the high temp was about 16, and the dish I had parked on PBS uses one of those inexpensive KUL1 lnbfs, and I've found that it will drift around 5 mhz when it gets cold outside. It's possible that the lnbf drifted far enough that the receiver lost the signal, although I've never seen this happen before, particularly on a high SR transponder like that. But the other thing is that when I switched back to my 90CM dish, which has a slightly more freq stable Invacom lnbf, that lnbf had not been powered up, because the diseqC switch only passes DC to the lnbf you're selecting, so it may have taken a while for that lnbf to warm up. Not a likely senario, but other than the transponder going down, I'm running out of explanations.

However the above senario does seem to point out a problem with the use of diseqC switches, because it is much better to have your lnbf powered all the time, as it keeps the temperature more constant in the winter, and tends to prevent moisture condensation in the summer.