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yamson

join:2007-10-14
Pittsburgh, PA

[HD] Many HD channels in low 100 MHz poor quality

Hi, I had a problem that started up last week where TLC HD would not come in at all (FIOS channel 639) and I got a "quick code" of 8801-0639. I now understand this to be a poor signal coming into my FIOS TV box. Since that time I have noticed other channels to be severely pixelated. Science Channel HD (622) and CNBC HD (602) as well. Going into the diagnostics mode, I noticed that all of these are in the low 100 MHz range. Channels higher up in the spectrum do not seem to have an issue.

CNBC HD is on 141 MHz and I'm getting a SNR = 27.1 dB (poor)
Sci HD is on 111 MHz and I'm getting a SNR = 26.9 dB (poor)
TLC HD is on 123 MHz and I'm getting a SNR = 0 (invalid)

In constrast...

USA HD is on 507 MHz and I'm getting a SNR = 36.1 (good)
TBS HD is on 567 MHz and I'm getting a SNR = 34.7 (good)
FX HD is on 381 MHZ AND I'm getting a SNR = 33.3 (good)

I have had FIOS TV/Internet/Phone for about 18 months now with very few problems. The coax in the house was pre-existing, and the FIOS installer used it without trouble. There is a splitter that splits the signal into the FIOS TV box and my broadband router right next to it, although I have had no troubles with the internet (or the phone for that matter).

Any suggestions?


Zero

join:2009-07-01
Collegeville, PA
Sounds like a wiring issue since you've done a pretty good job narrowing down which frequencies are causing problems.

If I were you I'd call up VZ tech support and explain to them your observations. They should be able to dispatch a tech out to check your splitter(s) and coax runs as well as verify the signal levels you're seeing. But before you go and do that just make sure all your coax connections are tight at the splitter(s) and at the endpoints.

kes601

join:2007-04-14
Virginia Beach, VA
kudos:2
Yep, definitely sounds like a cabling issue. I had similar problems that would bounce around between Spike HD, ES.TV, and HDNet (and whatever other channels are in those QAMs).

For me it ended up being a crimped coax in my attic. The previous homeowner had the excess coax excessively tightly around the rafters. I loosened it and fixed issues I had off and on for the past two years. At some point I will cut off the excess as it is somewhat of a hazard now if you have to go up in the attic, but the point of the story is to check your cabling.

yamson

join:2007-10-14
Pittsburgh, PA
reply to yamson
Thanks for the advice. Forgot to add that the FIOS box in the basement seems to get these channels okay, although the SNR's are still a bit low down there, they're not bad enough to pixelate. I'll check my cables and connections, and see what happens.

kes601

join:2007-04-14
Virginia Beach, VA
kudos:2
As Zero said, it could be as simple as unscrewing and reconnecting the coax at both the wall and STB. Start there.

PJL

join:2008-07-24
Long Beach, CA
kudos:3
Reviews:
·Verizon FiOS
reply to yamson
By the way, the reason a connector or splitter can impact only certain QAM channels while other are fine is the physics implications of the various frequencies involved. A loose or improper connection, or problem with the internal electronics of a splitter, impact a signal differently depending on the frequency. Sorry, I had to be a nerd for a minute.

yamson

join:2007-10-14
Pittsburgh, PA
said by PJL:

By the way, the reason a connector or splitter can impact only certain QAM channels while other are fine is the physics implications of the various frequencies involved. A loose or improper connection, or problem with the internal electronics of a splitter, impact a signal differently depending on the frequency. Sorry, I had to be a nerd for a minute.

No apologies necessary. My internal nerd was curious if there was a way to diagnose the specific problem based on the bad frequencies. For example, noise in the 100-200 MHz range implies a bad splitter, or something to that effect.

PJL

join:2008-07-24
Long Beach, CA
kudos:3
Reviews:
·Verizon FiOS
said by yamson:

said by PJL:

By the way, the reason a connector or splitter can impact only certain QAM channels while other are fine is the physics implications of the various frequencies involved. A loose or improper connection, or problem with the internal electronics of a splitter, impact a signal differently depending on the frequency. Sorry, I had to be a nerd for a minute.

No apologies necessary. My internal nerd was curious if there was a way to diagnose the specific problem based on the bad frequencies. For example, noise in the 100-200 MHz range implies a bad splitter, or something to that effect.

Hmmmm... a corroded or loose connection could also cause the noise. Oops the nerd came back.

CrobertGauth

join:2007-12-15
Glen Burnie, MD
reply to yamson
May also want to check the level on other boxes (even if they are working).
Could be that the problem is leaving the ONT. Other boxes might have enough signal, but this one might have a longer run or an extra splitter.
had that problem before where it was my connection at the ONT that was loose.

PJL

join:2008-07-24
Long Beach, CA
kudos:3
Reviews:
·Verizon FiOS
said by CrobertGauth:

May also want to check the level on other boxes (even if they are working).
Could be that the problem is leaving the ONT. Other boxes might have enough signal, but this one might have a longer run or an extra splitter.
had that problem before where it was my connection at the ONT that was loose.

Good clarification -- check all of the connections, including the one at the ONT.