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Do high SNR levels on Verizon FiOS affect Roamio Picture Quality

Discussion in 'TiVo Roamio DVRs' started by leepoffaith, May 4, 2014.

  1. May 4, 2014 #1 of 34
    leepoffaith

    leepoffaith Member

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    Apr 21, 2014
    Tampa, FL
    I'm having a problem with a few stations being pixelated here and there. Cinamax is one of them. The DVR diagnostic page shows all the stations have a 39 - 40 SNR with 97-100% quality. Most of the other stations are ridiculously clear and this only seems to affect a few. From the other posts I've read this has to do with the cable card model # (I have the newest one) and that was fixed with a software update. Do I still need to attenuate the SNR lower? If so, what level seems to work for everyone?

    Also, if anyone has any extra of these lying around they don't need I'd be more then happy to take them off your hands. :)

    Thanks in advance for the help.

    ~Lee
     
  2. May 4, 2014 #2 of 34
    lgnad

    lgnad Pantless Mofo

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    Feb 14, 2013
    Massachusetts
    there are definitely other posts on here from FIOS users having too high a signal level causing issues and needing to put an attenuator on the wire...
     
  3. May 4, 2014 #3 of 34
    leepoffaith

    leepoffaith Member

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    Apr 21, 2014
    Tampa, FL
    Yeah, I read those which is why I'm double checking. I thought that issue was solved with the new cablecard and software update, but I could have been mistaken. Before I go out and buy one I'd like to know for sure if possible.
     
  4. May 4, 2014 #4 of 34
    aaronwt

    aaronwt UHD Addict

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    Jan 31, 2002
    Northern...
    I'm on FiOS but the highest I have seen is a 38 SNR. But my channels have been fine. They range between 35 and 38 SNR.

    When I had my FIOS installation seven years ago, they put a 1Ghz, 8-way splitter on the ONT output because the signal was so hot. I used that splitter until recently when I replaced it with an 8-way 1.2Ghz splitter.
     
  5. May 4, 2014 #5 of 34
    Time_Lord

    Time_Lord Member

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    Jun 4, 2012
    I'm on FiOS and my signal strength is 100% with a SNR bouncing between 40 and 41.

    First the SNR ratio, higher is better, just simply means that there is less noise (garbage) in the signal. I'm going to guess that the TiVo will work with a SNR of >30 without much if any issues, once you start getting to 30 or below you will probably start seeing pixalation issues. Things that can cause a lower SNR ratio, (if cable TV) poor drop from the outside, bad coax cable, bad coax termination, unconnected coax cable or unterminated (unused ports) on a splitter which will act like an antenna.

    The signal strength, I'm not convinced that a high signal strength is a bad thing provided you are starting with a clean signal to begin with. I guess its possible you can over modulate the signal but at this point I'm having zero picture quality issues so I'm leaving well enough alone.

    Going back to CoAX for moment, I can't tell you how many times a friend asks me to look at their TV because they have a lousy picture only to find the CoAX wire bent at some extreme angle where it goes into the connector, (believe it or not there is a minimum bend radius of 2.75 inches) and the braid is pulling out of the connector, or some heavy furniture is crushing the cable (yes deforming the cable causes loss).

    My recommendation would be to use RG-6 CoAX, either /U (double shield) or /UQ (Quad shield) the Quad shield is probably overkill for the runs in a typical home. If you have RG-59/anything you are looking for problems as the wire is too thin and has a poor shield to carry the signals required for digital TV, it'll work for a short distance but even a medium size house maybe an issue.

    BTW, my house I wired a home run of RG-6/U for each TV to the basement to a single splitter in the basement.

    -TL
     
  6. May 4, 2014 #6 of 34
    CrispyCritter

    CrispyCritter Purple Ribbon Wearer

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    Feb 28, 2001
    North...
    As I've said previously (I thought to you), the TiVo SNR figure does not appear to be a true SNR figure; it measures something a bit different It is very well substantiated by numerous reports here that reducing a very high TiVo SNR level via adding attenuation or splitters can help picture quality.
     
  7. May 4, 2014 #7 of 34
    BigJimOutlaw

    BigJimOutlaw Well-Known Member

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    Mar 21, 2004
    The FiOS signal can be pretty hot. Tivo's sweet spot is said to be in the 36 SNR range. I have 40 SNR and haven't had too many issues, but mileage will vary.

    An attenuator or even a spare splitter behind the Tivo might help.
     
  8. May 4, 2014 #8 of 34
    nooneuknow

    nooneuknow TiVo User Since 2007

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    Cox Cable...
    TiVo's reading is NOT a TRUE SNR.

    If it was, the highest you could get it, the better.

    With TiVo, >36 can start causing A/V glitches, >38 can really make things messed-up, and >40 can damage the tuners, if the signal is reading 100% strength.

    I find I generally have to drop my signal strength into the 80-90 range, in order to keep my (TiVo proprietary) SNR in the 33-37 range. That's (roughly) my "sweet-spot", YMMV.

    I usually just advise against letting a signal be pegged at 100 strength, with a SNR >36, and as long as the strength isn't pegged at 100, higher SNR readings are less likely to damage anything (or shorten the life of the tuners). TiVo does have a protection mechanism, but it causes A/V glitches and A/V degrading, and isn't meant as a long-term solution.

    TiVo's warranty does NOT cover damage to tuners, caused by excessive, or "hot", signals. While some who have fried their tuners did get warranty replacement, others did not.

    Please (everybody), don't go preaching things about the SNR on a TiVo, that doesn't apply to TiVo's secret (and idiotic) way they calculate it.

    Good luck ever telling a cableco rep or tech that your "SNR is too high"...

    I've heard rumors that the Roamio is better at not burning-out, but is still not completely immune to it.

    Just because a TiVo seems to be "working just fine", doesn't mean it will continue on doing so, if it's having to deal with a "hot" signal...
     
  9. May 5, 2014 #9 of 34
    aaronwt

    aaronwt UHD Addict

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    Jan 31, 2002
    Northern...
    I certainly hope I don't have any issues. But if I do at least I got a four year warranty from BestBuy for my Roamio Pro. I shouldn't need to worry about my Roamio Basic with OTA since it's nowhere near as strong as my cable signal. Although I do have the Tivo 3 year warranty on it.
     
  10. nooneuknow

    nooneuknow TiVo User Since 2007

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    Cox Cable...
    Full disclosure: I've never heard of a 3rd-party warranty provider (outside of TiVo), denying warranty service for this. They don't have access to your logs, or any record of the calls you may have made to TiVo that may have brought the signal & SNR readings to TiVo's attention.

    I'm not speaking of just some one-off claim, or that long-running (gossip) claim like that the only people denied warranty over a drive upgrade, told TiVo they upgraded their drive, etc.

    I used to be able to keep my readings in the range that TiVo specifies on their website, before Cox went full 1GHz RF network here. Now, I sometimes have to let some channels drop too low, or just let some run too hot (sometimes both). I can only hope that as long as I'm making the effort, and not just letting most, or all, channels run hot, that I'm doing enough.

    They key in the TiVo-calculated SNR, is that it's not truly "too high", so long as the signal strength isn't pegged at "100" (which is simply the highest it can read). What does that also non-industry standard way of measuring signal strength equate to in the industry standard (dBmV)? My tests point to it (100) meaning anything from ~0.0 dBmV (a perfect level) to anything in the positive (+) range (even double the acceptable level, and beyond). TiVo's signal strength at any level less than 100 represents any negative (-) dBmV range, which can drop pretty low, before it truly starts degrading things.

    There can be scenarios where some have a ridiculously hot signal, and every channel reads 100 strength, and is accompanied by a high SNR (TiVo's version of SNR). These would be the ones in high danger of tuner-burnout. The built-in "protection" is some form of auto-attenuation, and has a limit to how much it can protect if always in-use, and just like any attenuator, it can only attenuate to a point. When somebody notices A/V glitches, often followed by what seems to be a loss of signal quality, that's sometimes the protection kicking in. It can either cycle in and out, or in extreme cases, always be in use. Sometimes the RS counts are a reflection of this mechanism cycling.

    I think that's enough schooling for the moment. I have to get caught up on other things, for now.
     
  11. kbmb

    kbmb Well-Known Member

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    Jun 22, 2004
    NH
    Making the effort? I didn't read anywhere on the Tivo box or in the manual that said I need to make a conscious effort to keep my cable signal within some "Tivo spec". :p

    If I don't have any issues, meaning I don't see picture dropping, pixelation, loss of signal.....why should I have to pay any attention to the Diagnostics screen?

    Last I checked Tivo didn't popup a warning message saying my signal was too hot....or maybe that's what those Bounty ads are? ;-) If they don't warn me, how could it be my fault if someday a tuner fails? Just curious.

    I had a TivoHD for 8 years and that had a 100% signal and 42-44dB SNR the entire time....never had an issue. Now with my Roamio Plus and Basic.....the Basic upstairs is 92-97% with ~35dB SNR, but the Plus is constantly 100% in the 40dB SNR range. (knock on wood) haven't had any picture issues. Is this "tuner too hot" a Premiere and above thing?

    I too have seen where signals on some channels can drop and quite frankly I think I'd rather keep things on the high side with a perfect picture than run the risk of signal loss or major pixelation.

    -Kevin
     
  12. nooneuknow

    nooneuknow TiVo User Since 2007

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    Feb 5, 2011
    Cox Cable...
    To each their own, YMMV, and keep knocking on wood...

    If you were to call TiVo, for some hypothetical issue, and they saw a constant "100% signal and 42-44dB SNR", it's not even hypothetical that they'd tell you it was too high. I'd bet a large sum of money on this. You can tell me you experienced otherwise (with TiVo CS), but I won't believe you.

    I'm not saying TiVo CS is always (or even remotely) right. But, there's no shortage of threads and posts that back up what I said, as opposed to what you say.

    I'll stick with what I said, and will (as a good-faith gesture), wish you continued luck, with your approach, on the matter.

    I never said everybody with a excessively "hot" signal will kill their tuners, only that it can happen, has happened, and is not covered by TiVo's own warranty, if they have proof that it was the cause of a tuner failure. I was also careful to state that TiVo has replaced units damaged by such conditions, making it a YMMV (and matter of luck) situation.

    I'll state that if you have channels that operate low, along with ones that are high, it's possible that your TiVo might never be on a hot channel long enough to damage the tuner. That's what I hope for in my situation. Once Cox went 1GHz, it became impossible for me to attenuate the all the "hot" channels to within TiVo's specs, without dropping others below TiVo's specs. More importantly, it was extremely hard for me to not induce low-signal issues on a great number of channels, by trying to bring down a few hot ones.

    I guess that the support page proving the acceptable ranges was made because TiVo had nothing better to do? No, it's part of any TiVo's true manual, and would be considered operational requirements.

    TiVo doesn't provide manuals with Roamios, and the manuals for the older models were basically "TiVos For Dummies", devoid of technical material, which incrementally became obsolete with each new software rollout.

    I'd rather have just ignored your post, but opted to make sure others that see it get to see a counter-post, and be as fully-informed as possible, before deciding what to do, if they do bother to check their signal levels.

    Even the lowly MSOs don't just plug in a STB or DVR without checking the readings, and adjusting them to within their own "acceptable" ranges. Since TiVo is also a retail product, in addition to being used by some MSOs, it becomes the retail buyer's responsibility to know the signal is within acceptable ranges.

    Unlike you, I choose to err on the side of caution, and prefer my signals a bit low, in order to keep the high ones from being way too high. I comprehensively check my whole home at least once per season of each year, due to seasonal signal fluctuations, and change my splitter/attenuators accordingly, if need be.

    I doubt you are on a 1GHz RF cable network, or you'd know that all this extra work I do, to monitor and adjust my signals, is forced upon me by the cable network I have to use, if I wish to use TiVo.
     
  13. kbmb

    kbmb Well-Known Member

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    Jun 22, 2004
    NH
    First off let me say.....I appreciate your posts, and don't think I was knocking on you. I was more thinking it's absurd for Tivo to deny anything to a user based on having them check something when a box is working perfectly fine. Most people I know buy it, plug it in and if it's works....then do about their days.

    Of course......this afternoon my Plus restarted for some reason and was stuck on the "Starting Up" screen. Had to pull the plug and restart.

    I guess that's the Tivo God's telling to me not to talk bad about them!!

    -Kevin
     
  14. nooneuknow

    nooneuknow TiVo User Since 2007

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    Cox Cable...
    OK. I guess I misread the "spirit" of what you posted. I'm kind of used to, and expect, some pushback around here. Sorry if I offended you.

    I wouldn't even recommend TiVo to many people, due to that expectation of just plugging it in and working (like you said). I often regret being the person who "recommended TiVo" to those I did. I wind up getting more verbal abuse about TiVo, than whatever computer or software I might have recommended to that same person, or persons. Some people are better-off with an MSO-provided and installed box, since signal-drift, and out-of-range issues, are the MSO's problem to adjust, not the end-user...
     
  15. mpnret

    mpnret Member

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    Dec 4, 2012
    Exactly what happened to me. I called for a totally unrelated issue and when they saw my signal and SNR they immediately assumed that was it and had me attenuate the signal down to their preferred levels. Turns out that I solved the issue that I called for on my own but the new lowered signals were now causing errors along with video quality issues. I went back to my original setup which is running hot and everything is good. My RS corrected and RS Uncorrected is even better when running hot. Thing is, is running "hot" really running "hot"? I doubt it.
     
  16. Time_Lord

    Time_Lord Member

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    Jun 4, 2012
    I would be careful about taking the word TiVo's tech support as gospel. I'll go out on a limb here and say they are judged on how many cases per day/week/month they close.

    I know I've called with obvious bugs, found others were having the same issue, you call and they know nothing about it and say you must be doing something wrong or if they don't know the answer they'll give you something that sounds reasonable, or push the problem as yours (we don't support the TiVo being connected to a switch). I'm guessing the story with to high of a signal strength came from some customer that decided he needed a signal amplifier which only served to boost the noise as well (you know, garbage in, garbage out), once the customer removed the amplifier his signal strength dropped to something below 100% and the TiVo started working reliably again. Thus this CSR spread the word that a high signal strength is a bad thing without understanding the whole scope of the problem.

    Just like I say my wife causes gray hair, I didn't have gray hair before I met her and her father didn't have gray hair before she was born, what's the common link? my wife, ergo my wife causes gray hair. In other words the logic although badly incomplete fits it must be correct.

    -TL
     
  17. CrispyCritter

    CrispyCritter Purple Ribbon Wearer

    3,652
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    Feb 28, 2001
    North...
    Sorry, you are just totally wrong here. There have been a large number of people just in these forums (well over a hundred at least) who have reported high signal strength and a bad picture, inserted attenuators or splitters, and have solved their picture problems. This has been true for every model of TiVo from the S3 on (well, probably not the Mini except indirectly). TiVo engineers talked about it here in the early HD days.
     
  18. nooneuknow

    nooneuknow TiVo User Since 2007

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    Feb 5, 2011
    Cox Cable...
    "Hot" is a term for an excessively strong signal. On it's own, it has nothing to do with actual heat.

    However, when the scope is broadened to include the tuner components, a "hot" signal increases the temperature of the components that have to process it. The amount of added heat is proportional to the strength of the signal.

    An attenuator is a simple resistor, designed to lower the signal. They will generate a minute amount of heat, as all resistors create heat.

    I think I've already gone out of my way to state YMMV, and there are many variables involved.

    Also, TiVo CS tends to push you to over-attenuate, in general. So, I can't rightly argue that you are in the wrong, or dispute your experience.

    I try not to use attenuators, due to the simple resistor method for attenuation. Attenuators caused me problems, as well, so they are a last-resort.

    Another way to attenuate a signal down is by using splitters. You can either change the number outputs to a higher number, which will result in a lower signal, and terminate the unused ports, or daisy-chain splitters to do the same thing. It's just always important to not leave unused ports "open" (without a terminator), as it allows noise into the signal via ingress, and can leak out signal, via egress.

    Due to higher frequency signals being attenuated at a different level than lower frequency ones, the higher frequency cable network you are on, the more of a PITA it is, to try and wrangle all frequencies, with a simple resistor-based attenuator.

    For me to say much more, I'd just be repeating myself.
     
  19. nooneuknow

    nooneuknow TiVo User Since 2007

    3,554
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    Feb 5, 2011
    Cox Cable...
    Yet, you seem to be upset that I called you out on your own gospel, and are now using TiVo's often clueless CS center to back yourself up...

    Another post where I'm best-off to just stick with what I have already said, and not repeat myself.

    Those wanting to know more, can find many threads, with many posts, that cover the subject thoroughly, in-depth, with many POVs and many experiences, accumulated over many years. I advocate taking the time to review the official TiVo support page on the subject, and taking the time to read the vast amount of data-points available in threads that predate this one. Everybody should make an informed, educated, decision. Everybody should not choose one of my views, or your views, without doing their own due-diligence on the subject.

    Example of an unrelated YMMV situation, that can go wrong:
    I found that I can recharge my Li-ion batteries faster if I use a charger that operates at a higher voltage and current than the correct one. None have blown-up, or caught fire, yet. That doesn't make it the right charger to use, nor do my results mean that somebody else doing the same thing won't cause anything from a life-shortened battery, to a catastrophic explosion and getting their house burned down. I know the risks, and made the choice to allow that very danger to be possible. So, I only do so in a pinch, and take other precautions to avoid the danger, which will always be there.
     
  20. mpnret

    mpnret Member

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    Dec 4, 2012
    I never meant to indicate that hot had anything to do with actual heat. What I did mean is we have no idea what 100% indicates in the TiVo world. I've attenuated with both attenuators and splitters and find that for my particular situation I'm better off running hot.
     

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