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High SNR & Missing Recordings

Discussion in 'TiVo Roamio DVRs' started by shortcut3d, Sep 18, 2013.

  1. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    Apparently my signal is hot from Comcast. SNR was 43-45 across all the tuners. However, my previous Ceton InfiniTV6 ETH did not report the signal so strong. I replaced the 4-way with an 8-way and the SNR only dropped to 39-41 across all tuners with strength still at 100%.

    Why do I care? The picture quality is great and channels seem to tune reasonably fast. But there was a missed recording yesterday evening due to not available. Once I noticed it was missed, I manually tuned the channel and it came up right away. There were no conflicts and overlap protection is on. The only thing I can think of is the high SNR.
     
  2. AdamNJ

    AdamNJ New Member

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    Aug 22, 2013
    Dunellen, NJ
    why would a high SNR cause a recording not to work/channel not to tune?

    Isn't a higher SNR better then a low one?
     
  3. rifleman69

    rifleman69 Member

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    Jan 6, 2005
    Oregon
    Not if it's too "hot". Put an antennuator on the line and see if it brings the SNR levels down and cause less problems. Your SNR levels should be closer to 35.
     
  4. code0

    code0 New Member

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    Sep 7, 2013
    Iowa
    My signal was too hot - the Roamio was reporting 35dB (seemed to be the max) and having major macroblocking issues.

    Chained a couple of splitters together to get it down a bit, and everything was happy. Ended up having Mediacom come back and supply the attenuator since it was a new cable install (previously was cable modem only).

    Since the attenuator was added (10dB in my case), SNR has been 30-33ish, and everything has been great.
     
  5. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    I guess I'm looking for confirmation that high SNR was the cause of the Not Available message for the missed recording.
     
  6. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    I reduced my hot signal using an 8-way splitter.

    I continue to get random Not Available messages for missed recordings. Is there anything I can do to troubleshoot? History really doesn't seem to help.

    All six tuners are constantly buffering when I flip through them using live TV. If I notice the Not Available message for a recording, I can immediately tune to that channel.

    The annoying thing is there is no warning about the not available recording.
     
  7. HarperVision

    HarperVision TiVo's Italian Cuz!

    5,275
    3
    May 14, 2007
    Paradise...
    Yes, put your Ceton back in and dump the beta Roamio! Why did you get rid of your PC Ceton solution if I may ask?

    PS - After re-reading what I wrote, I thought we could combine "beta" and "Roamio" and just call it the "Boatio", as in a new accessory for boats like a boat anchor because that's about as useless as it is in reliability with tuning and recording everything you want. Or maybe "Reamio" because that's what your a$$ feels like after shelling out all that cash for this thing. The TV ad jingle could be......."Ream Me?.....Ohhhhh"
     
  8. kbmb

    kbmb Active Member

    1,292
    15
    Jun 22, 2004
    NH
    I have Comcast and initially had a hot signal (solid 100's and SNRs in the 43-45 range). What's weird is with those I didn't have any issues.

    Anyway....I did chain some splitters together (until my attenuators arrive) to bring the signal down. In cases like these I think the signal level is more important. Like most people say....I high SNR in itself isn't bad....it's when it's a indication that the signal is too hot that the hot signal causes problems.

    Anyway.....I took -7dB off the signal to get some of the channels to be less than 100 for signal level. Again, wasn't having issues before and don't see issues now (I just like to tinker :p ) I still have channels hitting 100 and a 40 SNR, but will keep it around this and see if anything bad happens.

    Problem I have is Comcast messed with channel signals recently....so some channels....like Food Network have a lower signal so if I knock my signal down too much...that channel goes too low.

    -Kevin
     
  9. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    The Ceton InfiniTV6 ETH was no where near as stable or reliable as the TiVo Roamio Plus. Channel changes are faster with the Roamio Plus. No pixelation with the Roamio Plus. Don't get me started with PQ issues of the Echo. TiVo is hands down a better solution.

    How can I figure out the root cause of a missed recording? I also noticed that My Shows indicates the show is initially recording. Not sure when it stops and disappears. There's not even a partial recording remaining.
     
  10. skid71

    skid71 Member

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    Mar 20, 2013
    Do you have to use a Tuning Adapter? Although I don't have to use one, I have read posts that indicate a TA could cause issues.
     
  11. HarperVision

    HarperVision TiVo's Italian Cuz!

    5,275
    3
    May 14, 2007
    Paradise...
    Have you tried the HDHR Prime or the Ceton 6 tuner internal PCI-e card, or just the ETH? Don't get me started on that pos echo either! :p
     
  12. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    No Tuning Adapter. I agree the behavior is similar to TA issues, which makes it so strange.

    I had several HDHR Primes and they had really stable firmware late 2012 / early 2013. The channel changes were faster than the InfiniTV and no pixelation. The setup was not bad when I was using Xbox 360 extenders, forced into by 29/59 frame rate bug in WMC. Xbox 360s are power hungry, relatively noisy and have limited IR, so they aren't ideal.

    Overall, I'm much happier with TiVo, but need to figure out this missed recording issue. The lack of warning and log information is frustrating.
     
  13. HarperVision

    HarperVision TiVo's Italian Cuz!

    5,275
    3
    May 14, 2007
    Paradise...
    Which like I said in the other threads, points to a TiVo issue and NOT the TA, especially since you don't even use one!
     
  14. kbmb

    kbmb Active Member

    1,292
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    Jun 22, 2004
    NH
    After the 8 way splitter....what are your signal levels like and SNR?

    -Kevin
     
  15. k2ue

    k2ue Retired RF Engineer

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    May 9, 2002
    Victor, NY
    Good point, it depends how the "SNR" number is derived for presentation -- if it was true SNR then reception should be good with any reasonably high number, but not all conveniently implemented measures are accurate for very high SNR. However when the Signal Strength indicator is pegged at 100 it suggests the signal strength is exceeding the design range, and since there is an amplitude component in the signal, there is a risk of limiting, which would produce damaged symbols. It would be wiser to adjust the signal strength so it did not exceed 99 in the strongest case.
     
  16. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    Lowest I can get with my current set of splitters is 39 max on the current 8-way splitter. What I've notice is not all splitters are created equally. One splitter causes pixelation with the Tivo (no surprise as it did the same with the InfiniTV6 ETH), but cable modem speeds are high beyond spec.
     
  17. kbmb

    kbmb Active Member

    1,292
    15
    Jun 22, 2004
    NH
    But what are your signal levels like? Can you get any of the tuners to drop below 100?

    I have a hot Comcast signal to mine. All mine would be pegged at 100 and 43-46 SNR. Although I wasn't having any tuning issues....I decided to play around to get the signal levels down. Because Tivo doesn't show you above 100, it's tough to tell how much you need.

    I put two splitters basically dropping 10.5dB from the line. With that I get some channels to go into the upper 90's. A lot will still be 100 but the SNR will drop a bit. I figure as long as some are under 100, then overall the signal should be ok.

    I order some attenuators to replace the splitters.....waiting for them to arrive tomorrow.

    -Kevin
     
  18. shortcut3d

    shortcut3d New Member

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    Sep 1, 2013
    The SNR dropped a bit, but the signal has never fallen below 100 and appears to be pegged.
     
  19. kbmb

    kbmb Active Member

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    15
    Jun 22, 2004
    NH
    Wow.....I think an 8-way is an -11.5dB loss correct? That's a very hot signal then. Do you have an amp anywhere?

    I'd get another splitter if you have one, maybe a 2-way for a -3.5dB loss....and see when you start to finally see the levels go below 100. Chain multiples together if you have to. That's basically what I did to finally get -10.5 to see the levels drop from 100. Then after you find the number, order an attenuator that will give you that amount.

    I just ordered these:
    http://www.smarthome.com/7800/Signal-Strength-Attenuator-Pads-Mix-Bag/p.aspx

    I'll be starting with probably a -10 to see how that goes.

    -Kevin
     
  20. kbmb

    kbmb Active Member

    1,292
    15
    Jun 22, 2004
    NH
    Replaced my splitter-monster with a 10dB attenuator today. So far signal levels are usually at 100. Some stations will dip into 98-99.

    I do have higher SNR numbers (39-43). But honestly.....I would have a hard time believing a high SNR itself is bad if I know that the signal isn't too hot. I "think" I know this because I have some channels dipping below 100.

    Plus from Tivos page they say this:

    Clearly that means that you can have a signal over 100.....just not TOO hot.

    I really wish Tivo would show a true signal level. Seems it would help solve so many issues if they allowed people to understand the true signal level and not guess.

    Would also like to know what "some DVR components cycle in and out of "protect" mode to prevent damage" means. What does the Tivo do when it cycles things off? Is that where you can get the signal not found error?

    What's really weird in my splitter setup was......almost all channels were in the upper 90's. However, this afternoon A&E dipped to 67. No idea what Comcast is doing to some channels around here.....but I think I'd rather be a bit hot than too low.

    -Kevin
     

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