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Signal level frusteration, please help...

Discussion in 'TiVo Help Center' started by ahwman, Mar 3, 2013.

  1. ahwman

    ahwman Member

    234
    1
    Jan 24, 2013
    As a new TiVo owner (2 Premiere XL4's), I just want to enjoy my new toys but sadly that hasn't been the case... Out of the box I was getting a few random reboots approximately one every day or two. After speaking with tech support, they had me check my signal levels which were around 95% and SNR at 38. They told me that my SNR was too high and that it was most likely responsible for the reboots. They also mentioned that this could diminish the life of my TiVo's which concerned me. That said, I was encouraged to purchase a mixed bag of attenuators to try to bring the SNR down between 29-35 which I did. I started with a 3db which made no difference in the diagnostics screen, I then tried a 6db, again no discernible difference, then a 10db which brought the SNR down to 36 still too high according to support, so I finally tried the 20db which brought my signal down to around 86% and SNR to 34. The one thing I immediately noticed was that the RS corrected errors shot up from around 20-30 to well into the thousands on some tuners. Tech support told me that as long as I don't see any RS uncorrected errors, I should be ok. All of this occurred yesterday, and since then twice I have been watching TV on one of my TiVo's only to see the message "This channel is experiencing a network issue" on a particular channel or sometimes every channel. Rebooting the TiVo solves this temporarily. I'm so exhausted and frustrated because I feel like I have to choose whether to go back to no attenuators and risk diminishing the lifespan of my TiVo's, or deal with loosing my channels frequently and having to power cycle them...

    I appreciate any help...
     
  2. dlfl

    dlfl Cranky old novice

    6,996
    16
    Jul 6, 2006
    Near...
    This appears to be the continuation of the same issue you recently started another thread on:
    http://www.tivocommunity.com/tivo-vb/showthread.php?p=9538693#post9538693
    Double posting leads to confusion -- all the discussion of a particular issue should be in one place.

    You have bizarre signals that behave in a way I've never heard of. A signal level of 86 and SNR of 34 dB should give you excellent performance with NO RS errors of either type. I suspect some upstream device (e.g., a QAM modulator) is being overdriven and is creating errors in the signal. Whatever the cause, the problem is in your signals and would have to be fixed by the cable co. I would challenge them to hook up one of their STB's or DVR's and show it performs well with these signals. (If it does, I think I would consider giving up on TiVo at that point.)

    There are two issues with hot signals on TiVos:
    1. There is protective circuitry in TiVo tuners that will cut the signal off momentarily if it's hot enough to do quick damage.
    2. Signals that are hot but not enough to trigger the protective feature will damage the tuner circuits over a long term.
    Given you had to use 20 dB attenuation to get the signal below 100 I wouldn't be surprised if these issues apply.

    Network error messages are new to me. The obvious interpretation is it's related to your internet connection but how could that be affected by different attenuators in the video cable? I wonder if it refers to the OOB (out-of-band) signals that the TA and CableCARD use to communicate data with the cable plant? Perhaps these signals got too weak with your heavy attenuation.
    I can tell you how to check those levels if you want to get that deep into the weeds.
     
  3. ahwman

    ahwman Member

    234
    1
    Jan 24, 2013
    None of this makes any sense to me as prior to TiVo I had was using a cable company supplied DVR and NEVER had any issues tuning/losing channels. I also ran a Windows Media Center for many years with a cablecard/tuning adapter and never had to play with signal levels, etc. - it just worked. Everything from the pole to my house is less than 1 year old and I have no splitters anywhere. The reason I left WMC, was so that I didn't have to put up with other issues associated with maintaining a PC on a dying platform that was no longer being developed. I assumed I could buy a TiVo, plug it in and enjoy it - sadly this experience has been anything but that. Giving up on TiVo simply isn't an option as I have invested over $1,700 and am past the 30 day return policy. Quite frankly, I'm surprised that a consumer STB would be this finicky. I simply want to enjoy my TiVo's and hope there is a solution to this continuing issue...

    Regarding the network error messages, I was incorrect as I was going off of memory. Rather the message indicated an issue with the signal.
     
  4. lrhorer

    lrhorer New Member

    6,922
    0
    Aug 31, 2003
    San...
    That is total bull pookey. There is no such thing as a Signal / Noise ratio that is too high. There is such a thing as signal levels that are too high, but at 95 on the meter, this seems unlikely.

    'Mostly bull pookey. Very high levels can damage the tuners, but levels that high are pretty rare.

    If your signal levels are truly so high you need a 20dB attenuator to bring them into spec, then your CTV company has something seriously wrong with their plant, and they need to fix it. Levels anywhere nearly that high indicate either an incorrectly implemented plant, or else very high levels on the feeders, which invariably will result in a huge increase in 3rd order distortion.

    Call your CATV company and have them send out a tech. Have him measure the levels in your presence, and have him read them off to you. Don't allow him to brush you off with, "They look fine". If any of the digital carriers are much above +5 dBmV, then the levels on their plant are too high.
     
  5. dlfl

    dlfl Cranky old novice

    6,996
    16
    Jul 6, 2006
    Near...
    As you can see from this thread and your previous thread on the same topic, lrhorer and I are in substantial agreement with regard to your problems, and I agree with his recommendations for your service call. The fact that the other devices you mention worked fine with the exact same signals (correct? exactly the same signal?) makes this situation very bizarre, and very unfortunate if you really can't get out of your TiVo investment. TiVo tuners seem to be less robust than those in other equipment, but your problems are extremely unusual I believe.

    If you can't get things working, I would certainly try getting TiVo to allow a return. You definitely are on record with TiVo as having this problem before the 30 days aren't you?
     

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