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Bad cable connection affects only one QAM frequency?

Discussion in 'TiVo Help Center' started by dlfl, Mar 5, 2013.

  1. dlfl

    dlfl Cranky old novice

    6,996
    17
    Jul 6, 2006
    Near...
    TiVo HD with TA on TWC, Southwest Ohio. For several months now I've noticed that anytime an SDV channel gets assigned QAM modulator frequency 543 MHz, there will be severe video pixelation and audio distortion. The signal level is 40 to 45, occasionally going down to 0 and occasionally losing tune on the channel altogether. SNR is 28 dB and RS error counts climbing rapidly. This is the ONLY QAM frequency that has these deficiencies. All other frequencies have signal strengths of 80 to 100, SNR of 34+ dB, and no RS error counts. Even adjacent QAM channels such as 549 MHz.

    Today I had my second service call for this problem. The tech was the same one who came for the first call and this time I was able to show him the numbers for 543 MHz in DVR diagnostics. He immediately concluded the problem was upstream from my equipment and went outside to do something.

    Turns out the first thing he did was get into the tap box at the corner of our yard and tighten the connectors. And that immediately fixed the problem! (Although it may have introduced problems on other QAM channels -- only time will tell if the fix is complete.)

    My question for those who may know is:
    Can a poor cable connection cause severe attenuation just on ONE 6 MHz frequency band? It seems counter-intuitive to me but .... ???
     
  2. shamilian

    shamilian Member

    442
    0
    Mar 26, 2003
    NJ
    poor connectors as well as kinks in the wire can cause problems in a single or multiple narrow frequency ranges.
     
  3. dlfl

    dlfl Cranky old novice

    6,996
    17
    Jul 6, 2006
    Near...
    Can you expand on how this works or how you know this, or reference a document that discusses it?
     

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