Cable Card + Cable Modem Issue

Discussion in 'TiVo Series3 HDTV DVRs' started by wolfson, Apr 20, 2008.

  1. wolfson

    wolfson New Member

    17
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    Sep 19, 2006

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    I recently moved and I have run into an odd issue when trying to use my Tivo Series 3 and cable modem at the same time. Without the series 3 hooked to the cable line, the cable modem syncs perfectly and has a great signal. About 3 minutes after I hook up the series 3 to the same line, the cable modem drops signal. This 3 minute delay leads me to believe its not just a signal strength issue. Both of these were working perfect at a previous location. Curious if anyone has seen something like this before. I doubt Comcast is going to be willing to be much help as both devices are customer owned.
     
  2. bru_man

    bru_man Member

    34
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    Feb 19, 2002
    It probably is a signal strength issue. I noticed that the signal dropped significantly when I connected in the Tivo. My guess is the tivo has an internal splitter, so you cable line is actually being split 3 ways, one for the cable modem and then two for each tuner.

    You might want check the splitter between the cable modem and the tv/tivo. I have seen a lot of splitters that don't split the signal evenly so swapping the output lines from the splitter may feed more a stronger signal to the cable modem. If that doesn't work you may need an amplifier, your cable company might supply it for free or charge you a one time fee for it, or you can buy your own, you just need to make sure it allows two communication and works for the frequencies used by your cable company.
     
  3. wolfson

    wolfson New Member

    17
    0
    Sep 19, 2006
    It does appear that just plugging in the coax to the Series 3 significantly decreases the signal strength the modem sees. I have the cable modem on a two way splitter, which then goes into a 6 way splitter for each of the TV's in the house. This way the cable modem should be getting the best possible signal. The moment I plug the tivo in the downlink power goes from -14.8dbmv to -28dbmv which is too low to get sync. Tried a two way (cable modem compatible) amplifier and this did not help at all, so I have Comcast scheduled to come out and look.
     
  4. wolfson

    wolfson New Member

    17
    0
    Sep 19, 2006
    I really should have found the issue myself. This is a brand new house and the builders ran all the coax to a central distribution box. What they neglected to do was hooking the coax coming from outside into the input on the splitter but to one of the outputs, and some random drop to the input. Surprisingly there was enough signal for things to kind of work.
     

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