minimum MoCA performance

Discussion in 'TiVo Roamio DVRs' started by flar, Aug 31, 2014.

  1. flar

    flar Member

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    Mar 17, 2003
    San...

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    I recently installed a Pro + 2 minis for a friend and she mentioned that one of the Minis has complained about no connection to the Pro, but the situation usually resolves itself pretty quickly.

    I checked the network status on all 3 and what I found is that the 2 minis see each other with 280Mbits TX/RX rates and they each see the Pro with only about 120-140Mbits TX/RX. From what I've read that should be enough data rate for them to do their jobs correct?

    I'll probably have to crawl around under the house to see how the connections are split (every time I turn around I find another coax cable with a splitter with all 3 ends coming/going into walls and floors so I have little idea of the total topology, grrr).

    I did install a PoE filter where I thought it would work best. I found a coax amp and a 1:4 splitter in a closet in the garage. I'm pretty sure that this is fairly far out in the chain of splitters, but only a crawl under the house will likely prove that. I installed the filter just after the amp. I'm guessing that if I installed the filter between the Pro and the two minis that I would have a lot more than half rate, or could that be the cause? (When I'm over there later I guess I can remove the filter and double check, but I wanted to get some idea of the effect of the filter before I do any more experiments.)

    Would another amp hidden in the crawl space on the run to the Pro possibly cause the rate to halve?

    And could the half rate they are getting possibly be the cause for the occasional "no connection" errors in and of itself, or at least a smoking gun for the cause?
     
  2. JWhites

    JWhites New Member

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    May 14, 2013
    The record I hate amps when it comes to MoCA networking. My initial thought is if you install the PoE filter between the Pro in the minis they won't see each other at all because it would be filtering out the MoCA signal. Sounds like your friend has a rats nest of coax cable running through the crawl space (reminds me of my Grandfathers house lol) Generally (when no amp is in place) the filter should be put right before (or on the Input peg) the first splitter coming into the house. If I read things correctly, I'm thinking she may have too many splitters and unused open cables. (which if deemed unnecessary may render the amps unneeded). A general rule of thumb is the less open ports on the splitter better the MoCA connection. Like if you have a four port splitter and are only using three ports, cap the unused port because that could cause performance loss bleeding out (and if a coax cable is connected only on the splitter end it could act like an antenna and bring in interference like RFI and EMI) causing picture issues. http://www.amazon.com/gp/product/B000Q5W84U/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
     
  3. BigJimOutlaw

    BigJimOutlaw Well-Known Member

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    Mar 21, 2004
    General rule of thumb is that you want PHY rates over 200. Tivo says 180 and that's probably fine, but really over 200 should be attainable. (PHY rates are higher than actual data transfer rates, that's why the numbers are so high.)

    I can sympathize with trying to figure out a crazy coax layout. The Mini phy rates are perfect at 280. Clearly the common path leading from the Minis to the Pro is the obvious problem coax run, for whatever reason. It's unfortunately up to you to find and follow that path. :) Neither the amp or POE filter should be "between" these devices. And the splitters should be good grade 1GHz or higher.
     
  4. nooneuknow

    nooneuknow Well-Known Dismembered Member (Lurk Mode On)

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    Feb 5, 2011
    Whitewater, WI
    Are there any Cisco tuning adapters involved? They have an internal amp (more of an equalizer, but still an amp), which not only doesn't pass MoCA, but the MoCA can make the TA malfunction.

    I've seen a few reports of people getting minimal PHY rates, due to this. Most of the time it doesn't work at all. My current sig lays it out "Cisco tuning adapters should never be used inline (using the TA coax OUT port) to connect a TiVo, if MoCA is in use. Use a splitter w/PoE filter on leg to TA, use other leg for the TiVo. Enjoy!"

    Amps should always be kept upstream of any coax ports the MoCA needs to to pass through, or OUT ports it needs to traverse between. One hidden amp can make a whole house MoCA-impossible. If you have an amp at the point of entry, with a single amplified OUT port, it's better to place that PoE filter on that single OUT, than on the IN. This keeps the MoCA in the home, and out of the amp.

    Any unused splitter ports should have terminators installed on them (or change the splitter to less outputs). Any unused wall-plate ports should be terminated as well. It's even better to just disconnect unnecessary cables from splitters, and terminate the port, or best to change the splitter and not have extra ports. If you have a cable running to a room and the open connector, install a "barrel", like used in wallplates, then terminate that.

    You can use as many MoCA PoE filters as it takes to limit the MoCA to segments of coax where you need it, and keep it out of where you don't. While most don't do this, as they don't need to, it fits what you describe as part of a solution.

    As already said in other replies, you might/should be able to take out amps, if you eliminate/disconnect unnecessary coax runs.

    MoCA PoE filters stop MoCa completely, and reflect it back. They work from both directions. This makes them very handy for improving MoCA, by using them strategically-placed.
     
  5. flar

    flar Member

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    Mar 17, 2003
    San...

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    None that I've seen or know of.

    This is the topology I've set up AFAIK without going under the house.

    I'm betting this is the key issue here. I remembered that we had done some dissection of the cables in the upstairs when we had the TiVo temporarily up there while the downstairs cabinetry was retooled for the new TV and setup. When we moved the TiVo downstairs I didn't think we had reset the cables up there back to where we had them. When I was there today I took a quick check up in that room and found a coax coming out of the wall ending in a splitter with nothing attached to the out ports at all. I'll look for some terminators, but I think I can just hook it to some existing cables that it used to be connected to and that should terminate that end (it led to the spare bedrooms on the second story which are no longer used and don't even have digital adapters on them, but they still exist up there to terminate the cables). I think this is fairly close to the master 1:4 splitter that was in the garage where the amp was and the PoE splitter that I installed. This will be my first task when I get a chance to play with wires again.

    That may help as well, but I really think that bare splitter in the old upstairs spare room is causing most of the havoc I'm seeing.

    Thanks for the great suggestions and advice all!
     
  6. flar

    flar Member

    152
    2
    Mar 17, 2003
    San...
    Well I found all the cables that we had disrupted and disturbed during the renovations and put them all back into their original configuration connected to various devices that never get used and the rate didn't change much.

    Right before I fixed the cables I checked both minis and saw:

    Mini to Mini - ~280Mb
    Mini1 to Pro - ~260Mb
    Mini2 to Pro - ~130-140Mb

    I seem to recall that Mini1 was also down below 200Mb the last time I looked, but that was the figure I was seeing right then. After I fixed all the cables, though, I saw the same figures (and I even waited until some packets had accumulated in the packet counts to make sure that it was refreshing the information). Do I have to reboot them to make them refresh their rates perhaps?

    Otherwise, I may have to go into the crawl space to find out what is happening.

    One question on using PoE filters to cut off unused parts of the coax network - do they work in both directions? In other words, the threading on the filters is such that they can only be installed in one direction, and they are normally used at the main point of entry where the "downstream" direction can trap and reflect the signal within the house, but if I put it on a leg that doesn't need MoCA, then its "downstream" direction doesn't need any reflection - will it do the same job on its "upstream" end?
     
  7. nooneuknow

    nooneuknow Well-Known Dismembered Member (Lurk Mode On)

    3,559
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    Feb 5, 2011
    Whitewater, WI
    MoCA PoE filters block from both directions, and the thread orientation does not matter, unless the product says it matters (I have yet to see one, or hear of one that does, but stranger things have happened).
     

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