Choppy Audio and Video on TV without STB

Question

For about a week now, a 23" Samsung LCD TV that we have in our bedroom has been pretty much unwatchable because the video and audio signals have been extremely choppy, sometimes it won't even display an image or output any sound.  For this TV we do not have a STB because the TV has a Clear QAM tuner and we really only watch network programming on it.  All other video works fine on the TV in the bedroom; DVDs play just fine without any A/V signal interruptions.  The problem has happened before, but then gone away on it's own for a few weeks, then it comes back for a few days, then goes away again.  Our TV in our living room with the STB has been fine; no issues whatsoever.
I have checked all of our connections and none of them are loose.  So, my only guess is that there is a problem with the signal that is somehow corrected by the STB on our living room TV, but since we don't have the STB in the bedroom, the signal isn't being cleared up.
I live in South Riding, VA and have had FIOS for over a year and a half and love it, but this one issue is driving me insane (although, not insane enough to go back to Comcast).
If anyone has any advice on how to fix this problem, I would greatly appreciate it.

Answer 1

spacedebris wrote:
Yes, you can check the signal level, but it would require you to bring one of your STB's from another room into here.
What you would do is bring in any of your full size STB's and hook it up as if you were going to use it in this room. 
Once connected and you get the picture on the tv screen via the cable box...
walk up to the box and starting with it turned ON
Press  Power---->Select----->Select.   In that order
This should bring up a diagnostic screen on the tv.
Go to the line that says "inband service" and press the right arrow button
then find the line that says  SNR
This number should be between 31-37db
If it is 36db or higher, you will probably want an attenuator.
(emphasis added)
If the number is lower than 31, then the signal may not be strong enough. Both conditions, low and high will both cause the same symptoms.
WRONG!!  SNR is signal to noise ratio and not the signal strength - usually specified in dBm not dB.  Even an attenuated signal can have an SNR of 36 dB.
 Scott -
My TV (a Sharp Aquos) has a menu selection under DIGITAL CHANNEL SETUP for channel strength.  If you have something similar it will give you a relative signal strength.  In my case it is a number between 0 and 100 with anything between 50 and 90 working without issue.  It should also be a steady reading - a "jumpy" reading could possibly indicate an overload condition.
Unfortunately I don't know any other way for to check strength of signal.  If the attenuators work, it means you have an excess of signal and  probably will have no issues if the signal goes down a bit since the AGC (automatic gain control) in the TV should handle that variation.
If you don't want to buy the attenuators you can use splitters as attenuators (at least as a test).  A 2 way is typically 3.5 dB, 4 way is  typically 7 dB and cascading you just add the attenuation numbers.  If using splitters, be sure to terminate all unused ports on the splitters. Keep in mind that many TIVO users have required 10 dB or more to eliminate RF overload problems.
Hope that helps.
Message Edited by Keyboards on 05-08-2009 06:52 PM
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