Advice needed for troubleshooting weak signal / pixelation

Discussion in 'TiVo Roamio DVRs' started by anroz2984, Sep 29, 2017.

  1. anroz2984

    anroz2984 New Member

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    Sep 29, 2017

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    Hi,

    I purchased the TiVo Roamio OTA and have recently been experiencing a very weak signal / pixelation from WFRV-DT (CBS). As most of you know, TiVo customer support is less than helpful. I am hoping someone could take a look at the info below, as well as my TV Fool report, and offer advice.

    I use an Antennas Direct ClearStream V2 antenna and it is mounted on the roof, about 15 feet off the ground. I split the antenna signal using a PCT distribution amplifier (the signal is running to three tvs in the house). This amplifier claims to provide a gain of 8 dB.

    I have checked all of the connections and have verified the antenna is pointing the correct direction. I also have tried using different amplifiers / in-line boosters, but nothing has solved my problem so far. I even tried disconnecting the amplifier and connecting the antenna directly to the TiVo, but the CBS signal is still weak. I am aware that my TiVo has four tuners, weakening the signal as a result.

    Do you see anything on the report below that stands out as a reason why I am having a weak signal with only one channel? Any hardware advice or tips would be greatly appreciated!

    Thank you!

    TV Fool

    [​IMG]
     
  2. JoeKustra

    JoeKustra in the other Alabama TCF Club

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    You haven't stated what the diagnostics report as the signal level or SNR. That is a 1MW channel and should come in without any amplification. I would eliminate the issue of a bad tuner by:
    tune to WFRV
    restart the TiVo
    check that all tuners have the same level.

    Does your TV have diagnostics that show the signal level? It would be good to get a second opinion.
     
  3. sfhub

    sfhub Well-Known Member

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    Amplifiers amplify both signal and noise. Can you use a second device to see if that can pick up the channel?
     
  4. anroz2984

    anroz2984 New Member

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    Sep 29, 2017
    I have this problem on two of the three TV's that are hooked up to the antenna. On both of these TV's I tried disconnecting the amplified splitter and running the antenna directly to the TV. The pixelation is still present, but it is not as often, but the pixelation is still only on WFRV (CBS). All other channels have a strong signal, without or without the amplifier connected. I have tried three other amplifiers too to see if that made a difference, but the problem did not improve. I also tried a pre-amp at the base of the antenna, but that made all channels worse. When I connected the pre-amp, I made sure to disconnect the distributed amp too.

    After I restart the TiVo box, I am getting the info below from the diagnostics screen:

    Tuner:0 (Tuner 1, 2, 3 in parentheses)
    Channel: 5-1 (same for all four tuners)
    Frequency: 623000 Khz (same for all four tuners)
    Modulation: 8-VSB (same for all four tuners)
    Program Number: 3 (same for all four tuners)
    Signal Source: Terrestrial (same for all four tuners)
    Connector Type: RF (same for all four tuners)
    Channel Bits: 3151898 (same all four tuners)
    CableCard: None (same for all four tuners)
    Signal Strength: between 57% - 65%, not stable (Tuner 1 = 47% - 60%, Tuner 2 = 52% to 60%, Tuner 3 = 60%)
    Signal Lock: Yes (same for all four tuners)
    Program Lock: Yes (same for all four tuners)
    Search Complete: Yes (same for all four tuners)
    SNR: between 23dB - 25dB, not stable (Tuner 1 = 21dB to 24dB, Tuner 2 = 22dB to 26dB, Tuner 3 = 24dB)
    RS Uncorrected: 375 (this is much worse as various times of the day)(Tuner 1 = 5007, Tuner 2 = 7640, Tuner 3 = 11538)
    RS Corrected: 0 (same for all four tuners)
    RC State: Available (same for all four tuners)
    Current Tuning Status: Tuned: Success (same for all four tuners)
    Tune State: In Progress (same for all four tuners)
    etc etc

    The TV I have the TiVo connected to is a Vizio, and I am not aware of a way to see the signal strength on the TV, when the antenna is connected directly to the TV and through the TiVo first. I do get some pixelation with the antenna connected directly to the Vizio TV, but it is not as often. Still, pixelation is only occuring on WFRV (CBS), if the antenna is connected to the TiVo or if it is connected directly to the Vizio.
     
  5. JoeKustra

    JoeKustra in the other Alabama TCF Club

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    I would look for a way to get a reading closer to the antenna. Those signal and SNR numbers suck. You should have a signal of 72 and SNR of about 35 (about). Something is killing the signal from that station. I wonder if it is still at 1MW. Maybe their tower fell down. Something that affects only one channel would make me look at the channel, not my equipment. Sent them an email.

    WFRV-TV - Wikipedia

    I would bet that it shares a tower with WCWF. How are it's numbers? Check the locations for the two stations. Same location.

    WCWF - Wikipedia
     
  6. sfhub

    sfhub Well-Known Member

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    JoeKustra likes this.
  7. tampa8

    tampa8 Official Tivo User

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    Yes because I'm not sure anything posted precludes it being a signal problem not an equipment problem. In fact I suspect that first.
     
  8. kpeters59

    kpeters59 Well-Known Member

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  9. anroz2984

    anroz2984 New Member

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    Sep 29, 2017
    I did contact Dan @ WFRV and below is what he said:

    "WFRVs signal is at 100% and we output the same amount of power as WBAY. One thing that is not taken into account is the signal to noise ratio. WFRVs signal to noise is at least 3db greater then WBAYs, which means double the signal strength is getting to you. Being only 10 miles away, that means you are receiving a high amount of signal power and that amount is too much for your equipment to handle. I would make sure you have no amplifiers anywhere and then actuall pad down the signal another 6 to 10db. With less humidity in the air and leaves starting to come off the trees, there is less natural elements to inhibit the signal over the last couple weeks"

    Is he saying that I should use an attenuator to lessen the signal strength? If this is the case does anyone have a suggestion of which attenuator to buy where I would need to install this, before the distributed amp I would think?
     
  10. kpeters59

    kpeters59 Well-Known Member

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    You should be able to buy attenuators in 3, 6, 9 and 12db values for just a few dollars each.

    -KP
     
  11. V7Goose

    V7Goose OTA ONLY and Loving It!

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    Let's put this in perspective - for some of us, those numbers do not suck at all! They are MORE than strong enough to provide perfect video and audio on any channel that does not have some other problem going on.

    It is quite possible, of course, that those numbers "suck" in relation to what they should be, such as if you are located close to and in direct line of sight to the broadcasting tower, but I haven't tried to analyze that. I just don't want readers to start believing that a 57% signal (or any SNR in the 20s) is bad - that is NOT the case. For example, with no other signal problems, a Bolt should have perfect picture at 40% strength and an SNR of 16 dB. Now do understand that those numbers are not directly comparable between different models, so the minimum level for a Roamio is probably different. (I do not have a Roamio, but I have over 15 years experience with TiVo S2, S3 and S6 boxes, as well as specific training and a lifetime of experience with television and radio signal transmission/reception.)

    Most likely, your problem is specifically caused by multipath issues causing garbled and overlapping signals to reach the tuner. Minor changes in antenna placement or pointing can often produce BIG changes in the quality of the signal in this situation - sometimes a weaker signal can actually be a much cleaner signal.

    HOWEVER, I am also quite concerned that all four tuners do not show the EXACT same signal strength and SNR when tuned to the same channel at the same time. I personally have not seen that problem with any TiVo box I have ever used, so I would be very suspicious of that box.
     
    Last edited: Sep 30, 2017
    JLSLade57 likes this.
  12. JoeKustra

    JoeKustra in the other Alabama TCF Club

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    You are correct. I was looking at the distance and transmitter power to make my conclusion. I still think a comparison of the two channels would be informative since they share the same location.
     
  13. V7Goose

    V7Goose OTA ONLY and Loving It!

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    If the OP is in a very strong signal area (as indicated by a few of the responses), he should be more concerned with reflected signals than with simple signal strength. The solution might be as simple as a more directional antenna (I have not looked at what he is using, so that is just a generic comment), or one with less gain. Also, if he is in a very strong signal area, those relatively low numbers he is reporting can certainly indicate a bad connection somewhere in the cable plant.

    I would start the testing by dumping any splitters and amps, and just using one direct coax run to the TiVo/TV. Make one set of observations on signal strength, SNR and PQ on the TiVo, then manually move the same coax connection directly to the TV input and do the same observations there (comparing the TV results with the TiVo results can give a good indication if the issue is TiVo specific or signal specific).

    Finally, in strong signal areas, an excellent test is to simply get a different indoor/outdoor type antenna that can be easily moved around, and just run a new stretch of coax from the box to the new antenna on a porch or near a window - that TOTALLY removes the existing antenna and cables for an instant comparison.
     
    Last edited: Sep 30, 2017
    JLSLade57 likes this.
  14. mblloyd

    mblloyd Member

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    Personal experience has me in total agreement with these suggestions. (strong signal reflection appearing on the outer shield of your coax causing signal distortion)
     
  15. JLSLade57

    JLSLade57 New Member

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    Oct 6, 2017
    I just got finished dealing with this same problem going back and forth with Tivo and Xfinity. It took over a month to deal with. I have an XL4 Premiere, 2 Minis, and a Roamio Pro. The pixelation issue was only happening on the Roamio on live TV and not streaming, previous recorded or if Started recording Live on the XL4 and watched the recorded stream real time. I went through 4 or 5 Cable cards including swapping. Tivo sent me 3 replacement boxes. Xfinity and their lack of proper communication kept sending people not properly equipped to deal with the issue because they couldn't just replace their box and leave, came out 5 times. What ended up being the problem was the signal coming into the house from Xfinity was good enough for the XL4 at 82% but the Roamio was jumping all over the place from 64 - 92%. Once they boosted and corrected the signal coming into the house the pixelation was resolved. Even one of the Xfinity cable card reps said that the Roamio and Bolts seem to be more sensitive to the incoming signal. I'm not sure how this effects OTA but signal boosting may be required. Also removing any extra splitters you have will help too.

    Hope this is helpful.
     

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