771 loss of signal intermittent on SOME channels but not all... Bad LNB? Coax? example channel 355 Sat 103ba
All 4 of my receivers get a 771 loss of signal on a handful of channels including CNBCHD, MSNBCHD etc.. I'm wondering if I have a bad LNB and wondering if I can determine if the bad channels are all on one satellite and possibly the LNB or wht?. I see some maps that are old but the terminology doesn't match the receiver satellite receiver level check terminology. CNBCHD does it easily so I want to know which satellite and transponder its on so I can check its levels. One map I found online shows its on 103B with no transponder listed but the receiver has 103(s), 103(ca), 103(cb). I guessed 103(cb) = 103B and it appears to lose signal on the receiver level check on alternating odd transponders (1,3,5 ... 15) that come and go. That doesn't seem right but I don't know how odd/even transponders work or if there is something like a LNB control voltage that might be flaky or if this is normal and just looks bad or odd. When the odd transponders pop up they have values in the 80's while the even transponders have values from 89-95. But they come and go to "blank" as if the signal drops out. But I can invoke "low Res" mode and then it usually works at low resolution video.
My dish was aligned a few months ago when a DTV tech came over to fix this problem. At that time the problem was more intermittent and I wasn't able to show him. Now its worse. They are coming back in a few days and I was hoping I could get more info as last time the tech wasn't interested in even trying and wouldn't even get on my roof as he said "he couldn't". I'm not sure how one checks the 20 year old LNBs without getting on my roof as he aligned the dish hanging off a ladder.
Its very specific to certain channels and I mention CNBCHD ( Sat 103B no transponder) because it fails almost constantly now. It must be associated with a satellite, LNB, RF leakage from nearby WIFI etc, or something that hits certain channels and not most. The connectors are tight. Any thoughts appreciated. I just don't have much confidence with a DTV tech after my last experience. I've been with DTV for over 20 years and when ATT bought them, their service fell apart. At $250/mo with 4 receiver insurance - its bad!
Does anyone know how the mapping works plus why the odd transponders on 103(cb) would be flaky and if so does this mean a bad transponder or feed voltage up the coax?
My system looks about like this picture I found:
Thanks for any ideas?