Cannot watch/record OTA when connected to MoCA network

Discussion in 'TiVo Bolt DVR/Streamer' started by HockeyBeadles, Dec 10, 2016.

  1. HockeyBeadles

    HockeyBeadles New Member

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    Dec 9, 2016

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    I hope someone can help me on this, I have had a long week of setup and calls with TiVo support, so far all to no avail.

    I have tried several locations and setups on the path to correcting this issue and have ultimately isolated my Bolt to using only the coax runs necessary (I have bypassed all other coax runs in my house to rule out unknown issues behind the walls).

    The Bolt can stream content from Amazon, Hulu and Netflix just fine. The Bolt receives all our local OTA channels fine with great reception. JUST NOT AT THE SAME TIME!!! Streaming always works, however, OTA viewing/recording only works when the Bolt is disconnected from the MoCA network. When watching/recording OTA content, as SOON as the coax cable carrying the MoCA network touches the connector on the splitter, the viewing screen goes black and NO channels can be received.

    Here's my current isolated setup:

    In Utility Room:
    Internet from ISP ==> PoE filter ==> 3 way splitter
    3 way splitter ==> Cable Modem; MoCA Bridge; Coax to Bolt location

    At Bolt Location:
    Coax jack ==> 2 way splitter
    2 way splitter ==> Bolt; HD Antenna (w/PoE filter)

    Have also tried the above isolated setup with moving the HD Antenna to the utility room location b/c one TiVo support tech told me I had to insert the HD Antenna signal into the MoCA loop, which has subsequently been disputed by another tech. It didn't matter anyway as the same thing happens.

    Both splitters are MoCA rated 2350 MHz splitters. I have swapped the 2 way splitter with another MoCA rated 2350 MHz splitter. The 3 way splitter was purchased specifically for the above setup, but the OTA dropping when MoCA connected issue predated the introduction of the 3 way splitter into the configuration.

    I am at a loss and am starting to think that I have a bad Bolt on my hands.

    Can anyone help me? Anyone at all?
     
  2. krkaufman

    krkaufman TDL shepherd

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    Nov 25, 2003
    Quick read indicates that you may be mixing your cable TV/Internet signals with your OTA antenna signals when you make the connection between the utility room and the Bolt location. This combination doesn't work as well as the whole chocolate/peanut butter combo. At least that seems the case on a quick scan.

    I'd say it's a mystery why TiVo wouldn't have immediately highlighted the incompatibility of cable TV/Internet & OTA antenna signals, but then TiVo still has the following diagram posted to their help site, here:

    moca_abomination.png

    Just to be clear... this diagram is an RF abomination.*

    A quick review of the associated frequency ranges plainly shows the overlap conflict between OTA & cable signals -- and that MoCA, as designed, can coexist with either:

    OTA: 40-806 MHz
    Cable: 5-1002 MHz
    MoCA: 1125-1675 MHz​

    ---
    * p.s. Aside from the mixing of OTA and cable on the coax lines in the above diagram, there's no reason to have the PoE MoCA filters placed anywhere other than attached directly to the splitter, since there's little value in sending MoCA signals up a length of cable only to turn them back around, incurring unnecessary loss.
     
    Last edited: Nov 24, 2020
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  3. krkaufman

    krkaufman TDL shepherd

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    Out of curiosity, though not really central to your issue, what are the models for your cable modem and MoCA bridge?
     
  4. krkaufman

    krkaufman TDL shepherd

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    I did a bit of digging and found a previous diagram that should help with your situation.

    Leveraging the fact that MoCA frequencies conveniently reside up in the satellite frequency range, the following diagram illustrates how you can repurpose an antenna/satellite diplexer to get the antenna *and* MoCA signals to your BOLT, without the antenna and cable TV/Internet signals stepping on each other. The key is that a diplexer may look like a 2-way splitter, but it functions more as a conjoined filter, allowing only antenna frequencies through the "ANT (VHF/UHF)" port and MoCA signals through the "SAT" port.

    Critically, the "SAT" port may allow some cable TV signals through, but they'll be outside the range of your OTA antenna signals -- thereby eliminating the interference you've been seeing when simply bringing the signals onto your coax lines using splitters.

    Working from your description from above, your modem & MoCA bridge would be connected to Line #1 & Line #3, while the BOLT would be connected to Line #2.

    OTA-MoCA-Cable.png

    p.s. Your call on the 3-way splitter being a balanced or unbalanced splitter, depending on the signal levels you're seeing at the modem and BOLT.
     
    Last edited: Dec 10, 2016
  5. krkaufman

    krkaufman TDL shepherd

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    Prattling on a bit more as to what the diplexer would be doing...

    Recalling from above...
    OTA: 40-806 MHz
    Cable: 5-1002 MHz
    MoCA: 1125-1675 MHz
    And comparing to the Holland DPD2 diplexer pass-band specs...
    VHF/UHF(ANT): 40-806
    SAT: 950-2150​

    You'll see the antenna signals will pass through the "VHF/UHF" (ANT) port, while MoCA and just the top-end of the cable signal (950-1002 MHz, outside the OTA frequency range), will pass through the "SAT" port.

    Specs:

    Sources:
     
  6. hooper

    hooper Member

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    Sep 22, 2007
    Yeah that isn't going to work. ISP cable line needs to go directly to the modem in what is known as a home run setup. It CAN"t touch anything.

    Edit: The diplexer should(could) work, but I would try the home run setup personally.
     
  7. krkaufman

    krkaufman TDL shepherd

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    Good point. Having a dedicated line for the cable modem/gateway with a separate coax run available for the in-home MoCA/coax network would be the preferred solution, and should be the one chosen ... *IF* separate coax runs to the cable modem/gateway location are available.

    If there's only one coax run to the modem/gateway room from the distribution splitter, and a dedicated run can't be installed, then the above diplexer approach is available as a workaround. (Though the above diplexer approach would still be beneficial in bringing the antenna signal to the DVR with the least loss, even if the cable signal is isolated from the MoCA coax lines.)
     
  8. HockeyBeadles

    HockeyBeadles New Member

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    Dec 9, 2016
    Okay. A BIG "Thank You" to krkaufman. The diagram you provided represented exactly one of the iterations I had gone through during my setup process, with the exception that I was using a regular MoCA rated splitter and not a diplexer. After an exhausting search at every local outlet I could think of, I was finally able to procure a diplexer from a good friend and I am happy to report that I am up and running perfectly.

    Thanks again, your help is so much appreciated!!
     
    krkaufman likes this.
  9. krkaufman

    krkaufman TDL shepherd

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    Nov 25, 2003
    Great to hear; thanks for the feedback. Hopefully one of the posts above helped explain why a diplexer works in this situation, where a splitter fails.
     

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