MOCA intermittent picture / sound issues

Discussion in 'TiVo Mini' started by Kidcharlemange, Oct 12, 2016.

  1. Kidcharlemange

    Kidcharlemange New Member

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    Oct 12, 2016
    Since this is my first post, I'd be remiss to not thank everyone here on the forum. My wife and I moved a few months ago, which meant a new cable company. I was not pleased with the pricing of their DVR service, so I looked for alternatives. It was largely this forum that sold me on trying something different by purchasing a TiVo, and we have been pleased with it ever since.

    There is only one issue, which always seems to pop up on football Saturdays. My downstairs TV (which is the best in the house) connected to a TiVo mini has the picture start to pixelate, and the sound gets choppy or drops off. I have a tv upstairs with the TiVo Bolt, and this TV always performs well with a great picture. The two are connected by MOCA. I drew a (not so) fancy diagram of my system and put it on my Flickr: https://flic.kr/p/N23qR6

    I want to "tackle" the problem, which I'm sure is in the MOCA network. Interestingly, the RX power at the Mini is always around 0.6 dBm, the RX PHY rate is around 181, and none of the packets have errors. Since we are renting we can't run Ethernet cable between the upstairs and downstairs.

    I see two options:
    1.) is there an obvious error in my network setup? I know the amp is a little low bandwidth, but I had issues with the upstairs TV picture quality without the amp.
    2.) should I abandon MOCA and purchase a bridge to hook up the Mini by Ethernet? My existing AirPort is dual band MIMO wireless N. I ought to be able to find another one (used) to serve as a bridge. This ought to provide enough bandwidth, right?

    I really appreciate your help and expertise, TiVo friends!
     
  2. krkaufman

    krkaufman TDL shepherd

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    Would be worthwhile checking your current MoCA stats at the Mini and post back what it's reporting for TX/RX PHY rates and TX/RX power estimates.
     
  3. krkaufman

    krkaufman TDL shepherd

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    First, I'll repeat the above recommendation that you check and document your MoCA stats at the Mini before you make any changes. The current stats will provide a useful baseline against which to compare as you make changes to your setup.

    That said...

    The most obvious issue with your setup is how you have your tuning adapter and BOLT connected. Tuning adapters aren't designed to pass MoCA frequencies through their TV/RF Out ports, so (1) you'll need to split the coax line to connect the tuning adapter and BOLT+ directly to the coax, and (2) possibly an additional MoCA filter installed on the input to the tuning adapter.

    See the following post for more information: https://tivocommunity.com/tivo-vb/showthread.php?p=10961682
     
  4. krkaufman

    krkaufman TDL shepherd

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    I'd also be interested in the brand/model # of your 1x8 amplifier (as most older amps aren't MoCA friendly), and I'd recommend replacing any splitters with known-good MoCA-compliant splitters. (e.g.)

    Correcting the tuning adapter & BOLT+ coax feeds may be sufficient to get your MoCA network working better, but ensuring that your amp and splitters are MoCA-compliant would also be beneficial.

    And do you need an 8-output amplifier?

    edit: p.s. Thanks for the diagram; they really help.
     
  5. thyname

    thyname Well-Known Member

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    Dec 26, 2010
    N. Virginia
    I would also suggest checking Bolt whenever you experience pixelation on Mini.

    From my experience, issues on Mini are directly linked to issues with the host DVR (such as "hot" SNR levels, channel strength, CableCard issues, tuning adapter, MoCa), and they manifest themselves on Mini first before than the actual source of problem - host DVR.

    Just a thought.
     
  6. Kidcharlemange

    Kidcharlemange New Member

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    Oct 12, 2016
    Thank you all for the help. Seems like trying to fix the MOCA is the better way to go.

    The amplifier is PCT-VC-5U that I got from the cable company. I had issues with the upstairs TV signal strength without the amp, but maybe splitting the signal at the SDV box would help?

    Network stats have been pretty stable whether the picture quality is good or not.
    TX PHY rate is 281 Mbps
    RX PHY rate is 181 Mbps
    TX power 16 dBm
    RX power 0.612 dBm
     
  7. Kidcharlemange

    Kidcharlemange New Member

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    Oct 12, 2016
    Also, every time I've had the issue on the Mini, the Bolt TV picture is fine.
     
  8. fcfc2

    fcfc2 Well-Known Member

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    Feb 19, 2015
    Hi,
    A little confused, the PCT-VC-5U is actually a 5 port device with 4 of the ports being amplified. The VOIP port is not amplified and is supposed to be used to feed a telephony cable modem.
    When using such an amplifier, there is no benefit if using MoCA to feed your minis as the MoCA frequencies are not being amplified.
    The TA is not configured according to the best practices form as mentioned by kr already.
    If you want to proceed step by step, I would recommend first replacing that 2 way splitter with one of the 3 ways that you can find on the already provided link with the legs feeding the TA, Bolt, and cable modem and if possible, an additional MoCA filter on the input of the TA. If you get an unbalanced 3 way, you can play around using the lowest rated 3.5dB leg with either the Bolt or the cable modem if you have issues with either device.
    Your diagram only shows you are using really 2 of the feeds off of the amp. In any case, I would also consider replacing that amp with a standard MoCA rated splitter from the same source already mentioned but with just enough outlets that you are actually using. The original MoCA filter should be placed on the input of that first splitter.
     
  9. krkaufman

    krkaufman TDL shepherd

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    Definitely.

    And just try the simple split of the coax to the tuning adapter and BOLT+ as a start. Further improvements can be made to bring your setup in-line with MoCA requirements -- and further improve performance -- but this change should make a big difference.


    This amp...?
    PCTVC5U-2.jpg

    If so, which outputs are currently in use for your coax runs to your modem/BOLT+ location and to your Mini? (Since you're trying to pass MoCA across the output ports, you MUST NOT use the unamplified modem port to connect any coax runs where you need MoCA, since this port originates on the upstream side of the amplifier.)

    How is this amp powered? Are you using the "PWR IN" port or a power inserter connected to one of your output lines?

    Also, have you capped the unused ports with 75-ohm terminators (e.g.)?


    ----

    p.s. For future reference, the PCT-VC-F15U would be one MoCA-compatible alternative to your existing amp, with similar specs, should an amp be required and your MoCA signals are still not satisfactory after splitting the tuning adapter and BOLT+ feeds, and updating your splitters to MoCA-compatible models.
     
  10. krkaufman

    krkaufman TDL shepherd

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    Nov 25, 2003
    After you've split the feeds to the tuning adapter and BOLT+, it would definitely be worthwhile trying the above to see if you really need the amp.

    Even if you had more than 2 coax runs to accommodate, your setup indicates that you could have an initial 2-way (MoCA-compatible) splitter* with one output feeding the modem/BOLT+ room and the other output feeding whatever sized splitter is needed to provide runs to the other rooms where you just need a MoCA signal. (For now, it appears you only have 2 runs total, so a single 2-way splitter* would suffice.)

    * ... with a PoE MoCA filter attached to this initial splitter's input, just as you've done for the initial amp.
     
  11. Kidcharlemange

    Kidcharlemange New Member

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    Oct 12, 2016
    Thank you all for your expertise. I switched the upstairs setup to a 2GHz 1x3 coax splitter which feeds the Bolt, SDV box, and cable modem. I placed a POE filter on the SDV leg of the splitter. Just like that, the stats got better:

    TX PHY 280 Mbps
    RX PHY 275 Mbps
    TX power -18 dBm
    RX power 0.484 dBm

    I'm guessing the issue before was the receive wasn't fast enough.

    I think that will do. I still have the amp (my mistake, it was 4 output and 1 modem output). It does not use a power injector - the power "wall wart" converts to coax which connects to a special input on the amp. If things go bad on Saturday, I'll switch in the coax splitter.
     

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