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FIOS TV pixellation fix - attenuate to SNR 31

Discussion in 'TiVo Series3 HDTV DVRs' started by AbMagFab, Nov 19, 2007.

  1. necrotaur

    necrotaur New Member

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    Feb 25, 2008
    Sorry, I thought I said I was in VH08 (Philadelphia). As far as I am aware - V* standardizes on frequencies:

    195 MHz = ESPN News (Channel 572) and Starz4HD (Channel 845)

    If Someone can tune to 572 or 845 and check - if those are your numbers, and if the the frequency in the DVR Diagnostics Screen (under Messages and Settings->Settings->Remote, Cable Card & Devices->CableCard Decoder->Configure CableCard 1->DVR Diagnostics) matches 195 MHz, can you report if it comes in ok?

    Thanks,

    Steve
     
  2. sinanju

    sinanju Member

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    Jan 3, 2005
    My bad. I must have grabbed the wrong channel from the guide when I popped it up.

    572 is on 195MHz for me, so you're right about that. The channel looks fine here in Massachusetts... that's with the cable split 4 ways and an additional -12dB applied at the TiVo.
     
  3. necrotaur

    necrotaur New Member

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    Feb 25, 2008
    No prob.

    I have a variable attenuator and have gone from 0 to 20db with no change in signal strength. I can vary the SNR from around 33 to 29 in the range, but RS uncorrected just increments insanely fast. I could see it being a hardware issue, but it happens on both TiVos with all 4 cablecards. I have unused connections terminated, validated all connections are tightened, filtered out MOCA with diplexers and attenuated the signal, and still this channel is an issue.

    My neighbor has a Moto HD box and I got him to tune 572, and it comes in ok. Argghhhh - this is so frustrating.

    Anyhow, thanks for checking.

    Steve
     
  4. percyad

    percyad New Member

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    Jan 6, 2007
    Okay folks - I've been quietly reading and trying different suggestions mentioned over the last few weeks trying to get my TivoHD working with Verizon Fios here in Buffalo, NY. I've had Verizon here twice (big surprise - they found everything within specifications), changed out virtually every piece of cable and splitter, tried three different low-pass filters (two diplexers and a LP filter provided by Verizon), all different attenuation values, disconnected the cable from the router and I still get bursts of RS Uncorrected errors and severe pixelization.

    And yes, the Motorola STB and QIP-7214 I also have in the house have perfect picture all the time. (I've even tried turning them off and disconnecting them to see if they are the source of the problem)

    I am convinced that there is something else going on here. If it were just attenuating the signal, I would have this fixed weeks ago.

    So, what I'd like to do is get a little more scientific about narrowing down the problem beyond my specific situation.

    If you have tried all the above and are still having problems, how about posting the following information about your installation:

    What city do you live in?
    Model # of the ONT:
    Model and DOM of the TivoHD/Series3?
    Do you have any Motorola devices on the cable too?
    If so, which devices?
    Is there a 860MHz low pass filter on the ONT?
    Have you tried the low pass filter?
    Attenuation? How much?
    Actiontec Router?
    Using Cat-5 Ethernet or MOCA?
    What channels have problems?
    When does it happen (all the time/in bursts/certian times of the day)?
    Any other symptoms?

    Maybe we can figure this out for Tivo and Verizon and help them fix it!
     
  5. sinanju

    sinanju Member

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    Jan 3, 2005
    When reading through the thread, you must have missed my invitation to collect Verizon problem report numbers and consolidate them on 12/2.

    Unfortunately, there didn't seem to be much interest here and the ones I did collect and present in consolidated form to the Verizon Chronic Issues group for their consideration resulted in a simple, "Don't bother, we know who they are."
     
  6. techjunkie

    techjunkie New Member

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    Jul 25, 2003
    I can see that this thread has grown tremendously, but putting aside everything after page one for the moment, thanks to the OP for the original advice. My issuse is resolved. Too much attenuation fixed the "broken" channels, but "broke" working channels. Finding the right level was easy though:

    I have two Series 3 HD TiVos and three FiOS SD boxes and the FiOS modem all connected by RG6 home runs back to a Verizon-provided 6 way splitter. Despite the attenuation naturally provided by the 6-way splitter, I still had horrible frequent pixellation only on the SHO HD channels 868-874 on all four TiVo S3 HD tuners (2x2). Every other channel was perfect.

    Having been through a similar situation with these TiVos and Cablevision of LI previously, I anticipated painstaking phone calls and cable card issues, boosters, shoulder shrugs and finger pointing. To my relief, Verizon was support was top notch - leagues ahead of Cablevision. Upon calling them, after only a very brief wait, the first person the automated system connected me to was well versed at cable card issues. I was pleasantly surprised. As a preliminary attempt to solve the problem, she reset all my equipment remotely, but being that I was not home at the time, I'd have to call back upon returning home to see if the resets resolved the issue, or if it would have to be escalated to some other team. Having dealt with Cablevision's cards and technicians, I was fully prepared to arrive home to find all my channels completely lost.

    After ending that call, I googled the issue and found this thread. (Thanks again.)

    When I got home, I was pleased to discover that although there was no improvement, all my channels were still there.

    I dug up a 10db attenuator that I had laying around (Cablevision had put it on their own equipment to protect it from the booster they installed trying to fix pixellation on some HD channels when they were my provider) and tried it on one of the TiVos. It didn't completely solve the problem, but did make an improvement, leaving less significant, less frequent pixellation on the affected channels and did no harm to any others.

    Word of caution: unplug your TiVo from the AC outlet before adding the inline attenuators. I managed to do something to my cable cards by adding it while the TiVo was powered on and even after restarts, found I had lost most of my subscribed channels. It would start up already tuned to a working SHO HD channel but after surfing away from it, I could not pick it up again. A second call to Verizon proved to be just as impressive as the first. This tech. reprogrammed my cable cards successfully in a few minutes and was surprised to hear that I had already spent $$ ordering my own attenuators. He was prepared to send a technician out for a visit to solve the problem and made no mention or threat of any charge if the problem was deemed to be with my own equipment.

    I had already purchased new in-line attenuators online from Home Network Supply because the vendor linked on page 1 was out of stock of the variety pack and I wasn't sure I'd be able to find the one that I mentioned before. I got 2x10db, 2x6db and 2x3db (no 2db offering from HNS). They arrived two days after ordering and I'm happy to report that things are almost perfect now.

    16db was too much attenuation - while it fixed the SHO HD channels, it CAUSED bad pixellation on ONE Encore channel, 360. I dropped back to 13db (10+3) on one TiVo and found only the slightest, infrequent pixellation on ch. 360 and no problem on the SHO HD channels, or any other. On my other TiVo 3 I used two 6db attenuators, but because of the length of the two combined and the lack of space behind that unit, for flexibility's sake, I had to add a 6" piece of RG6 and a female to female coupling connector. I'll consider that unit to be attenuated by 12db + whatever the short cable and coupling connector adds (12.2db?). The results are almost identical to that of the first unit. I actually have component cables run between rooms, leftover from a time before the two units could share programs over ethernet. This allowed me to do a PIP comparison of both units tuned to ch 360 at the same time. Each would occassionaly suffer minor pixellation, but oddly enough, never at the same time or on the same part of the screen.

    In the end, the only pixellation I ever see on any of the four tuners is the occasional pixellation on a single channel (360), and no loss of audio.

    All in all, this was an inexpensive fix that was easy to implement.

    I suppose I could call Verizon again and have them come out and tinker with the signal strength on specific frequencies to just attenuate the fequency range of the originally affected channels but it's really not worth the trouble just for the occasional pixel pop on ch. 360. (If it were say, a major HD network and happend during LOST, I would call them, or maybe try 11-12db attenuation first.)

    I called Verizon years before FIOS was available in my area to see if it would support cable-cards, and then purchased my TiVo 3 units immediately after. After two years of waiting for FiOS to be available in my neighborhood, now that I finally have both, I couldn't be happier with the two combined. For the first time since going Hi-Def, (having tried multiple TiVo versions and TV providers along the way, and few horrid provider DVRs) I am once again finally as satisfied as I was with Dish Networks and my turbonet and storage modded Philips TiVo 1, before ever HDTV existed.
     
  7. webin

    webin New Member

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    Feb 13, 2008
    Hillsboro,...
    That line made me laugh... it's like going to the dentist, and being happy to still have a working kidney when you leave.

    I'm glad you were able to successfully find a solution to your pixellation, and your story is excellent information. Happy fiosing (that's a word, right?)
     
  8. techjunkie

    techjunkie New Member

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    Jul 25, 2003
    I should know better than to tempt Fate by posting out loud. After enjoying the last half of the Matrix on one HBO HD channel, I switched to Transformers about 30 minutes in on another HBO HD channel. About an hour in, pixellation on that channel got so bad, it actually stalled at one point, requiring me to switch channels to get it going again. :mad: I powered down, removed the 6db attenuator and left the new 10db one in. Maybe the new one is somehow stronger than the old 10db one I had, because the SHO HD channels don't show any pixellation and neither does Encore on 360. I made it through the rest of Transformers without a hitch. Since then I've been switching between Disturbia and The Matrix which both started on other HD channels just as Transformers ended. So far so good. Fingers crossed that this will keep working at all hours of the day.

    I checked the 6-way in the attic - each output is labeled 11.5db. I have an antronix 8-way that must attenuate more, so my next move if things go south again is to try that switch with the 10db attenuator. If still no joy, then I'll call FIOS. Not sure what the bedroom TiVo is doing signal-wise. It's 1:20 AM. Time for bed. ; )
     
  9. techjunkie

    techjunkie New Member

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    Jul 25, 2003
    I realize I'm late to the party here, and apologize for not reading through the entire thread before posting this, but it occurs to me that the TiVo probably attenuates the entire 0-1000 Mhz frequency range up or down internally based on some sampling, but can't selectively attenuate specific frequency range blocks up or down. If that's correct, then knocking the entire frequency range down with an attenuator isn't a perfect solution if the problem stems from some blocks having stronger than average signal strength and others having weaker than average signal strength.

    EDIT: hey guess what? I'm still up on a work night because I decided to wade through 14 pages of this thread. still dont' know what my bedroom TiVo is doing because I haven't been to bed yet. not that it would matter, the s/n ratio probably changes at different times of day and now isn't when I usually watch TV. So, carrying on... having just received FIOS, I'm pretty sure I've got the newest components available, and I've read that it might be necessary to equalize the signal strength across all the entire frequency range so my next question is this... how? Is there an equalizer that I can purchase, or does FIOS have to equalize the signal for me? Beginning not to care...must sleep.
     
  10. hmm52

    hmm52 New Member

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    Feb 25, 2008
    Lower...
    techjunkie - I read your post before going to sleep but didn't respond. I think you asked, but edited out later, something to the effect "Is there something VZ can do on their end to tweak their settings (to clean up their feed)?" The short answer - Yes!!

    I've been meaning to enter the tempest between wm2008 and Irhorer but haven't made the time yet. I have a long list of speculations, beliefs, based on some years of living with various cablecard devices, FiOS and Comcast. The one that apples to your situation is this:

    Adjusting signal level through attenuation may and often does help devices cleanly tune signals with line errors. But the faults causing tiling/pixelation are usually not a result of signal level itself. While the errors can be introduced anywhere in the feed - source --> VHO --> CO --> street --> home distribution, most of my problems, and probably many others', were gifts from the CO (central office). The times when my problem frequencies were checked at street cable end entering ONT by top VZ techs, they were loaded with line errors; the matter was then bounced to the CO and completely remedied shortly thereafter (less than 2 days).

    It's worth checking everything in your house anyway and Verizon will probably require that before checking the street feed - my experience with the top techs also. I found FiOS service to be most responsive when it was new to my area; Internet then TV. The challenge is in getting the right tech to take an interest in your case then pass it on the CO if necessary. Good luck with that. There is only so much a subscriber can do in house. Rather than putting much energy into calls to TiVo or into microfine tuning your signal level, I recommend trying to push the issue to your CO. My best guess is that the cause of your pixelation is there.
     
  11. Feb 7, 2009 #551 of 866
    exdishguy

    exdishguy New Member

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    Apr 30, 2004
    I've had FIOS out to my house so many times I've literally lost count. The last trip I had an arrogant a$$ FIOS network tech assigned to my field tech walked the tech through testing every drop with his sunrise meter starting from the ONT out. They replaced the ONT, checked the fiber connections at the ONT and street but refused to check the CO. The result is that with attenuators I have most channels working pretty well - but then again, I've had that for a while now. The problem channels were on my local HD channels and now they've moved into the 900s.

    Interestingly enough, each drop my tech tested with his sunrise meter FAILED but the network tech had him read the BER, SNR, and dbmV to him and said the drops were fine. But here are my concerns with the findings:

    1. The SNR fluctuated wildly on some channels. I had to ask the tech to specifically plug in the freq to test the problem channels. Typically the techs only check four channels across the band by default.

    2. The gain varied across the band quire a lot - I think channel 3 was +6dbm and channel 120 was over +18dbm. The network tech had the field tech attenuate the signal at the ONT by 3db but I still had to add as much as 14db at each of my Tivos.

    3. Of course, the Moto DVR worked fine. I had the tech go into the diagnostic screen and their counter for corrected/uncorrected errors were zeros and every now and then I'd see errors but the counter would reset instead of cumulatively displaying them.

    4. Also noteworthy to me was a stat called "AGC 12%". The Moto boxes have an AGC built in and according to Tivo, the Tivo's do NOT have an AGC.

    Soooo...here is my latest theory:

    a) that Verizon purposely jacks up their signals output and does so unevenly across the band. Why? Because they know that their equipment can handle it with the AGC they had Moto put into their DVRs.

    b) that attenuation may never work for some installs, such as mine, because the Tivo's don't have an AGC and my signals range so widely from one end of the band to the next. Some installs may be fine if the output power from the ONT is flatter across the band.

    c) fiber path and/or CO problems can certainly be a contributing factor in some installs. I cannot rule the CO out for mine but Verizon has decided to tell me that my "Tivo's aren't compatible with their service". Nice to know after they told me it was when I bought the service.....FCC report filed yesterday.

    This AGC thing really make a lot of sense to me but someone like Irhorer to comment on the technical viability of this theory. But an Automatic Gain Control, if present on the Moto and not the Tivo, would in fact automatically attenuate the signal to 0dbmV which may well be a major reason why the Moto boxes work with FIOS and Tivos are hit and miss at best.

    If FIOS is doing this intentionally then it fries my a$$ and I may dump them and go to TW as soon as I can get a TA. Not sure if they'll be any better and I know the bitrates will be lower...but I have principals and cannot forgive this if that is what FIOS is doing.

    Now if Tivo designed a box without an AGC that was intended to be sold aftermarket to cable customers all over N. America....well, that seems silly to me as well. But this is a design omission that cannot be changed in the field so I won't get anywhere with that. Besides, if the cable companies weren't doing everything they could do to undermine Cablecards and customer equipment (like Tivo) then this would not be an issue. But shame on Tivo for not anticipating that the cable companies would not give up their monopolistic and unethical ways so easily.

    One last rant...Moxi looked really interesting until they confirmed that their $800 box cannot stream video between other Moxi boxes on your home network. Are you friggin' kidding me? So if I buy $2,400 worth of Moxi HD DVRs I cannot share content between them? Talk about product managers with their heads up their a$$es.

    Update - Tivo L2 now confirms that they have AGCs....I couldn't believe it when they told me they didn't.
     
  12. Ziggy86

    Ziggy86 Member

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    Jun 22, 2004
    If AGC is not built in for Tivo can they (Tivo) make such a thing for their customers who are experiencing problems with pixelation as an ad on? I would even purchase it just to get a good picture if it helped.
     
  13. exdishguy

    exdishguy New Member

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    Apr 30, 2004
    Actually, the Tivo's have AGCs - I could not believe this when one of their 1st level support guys told me this. Sure enough, a L2 tech told me that they do in fact have AGCs.

    I just picked up some of the Radioshack variable attenuators mentioned earlier in this thread and had the Verizon tech come by with his Sunrise meter to dial them in. Things are improved but it is only the first day...

    Right now I still think that the Verizon signal is too hot and isn't flat enough across the band. +6dbm to +18dbm as measured from the ONT by the tech. So while we can usually attenuate and fix most of the band, invariably we start seeing issue pop up elsewhere in the band. So if my variable attenuators don't work, I think I am going to push to get Verizon to flatten the signal across the band....at least bring it within a 5dbm swing rather than 12dbm.
     
  14. exdishguy

    exdishguy New Member

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    Apr 30, 2004
    BTW - I work for a mixed-signal semiconductor company and have spoken to one of my RF engineers about designing a circuit that effectively "equalizes" the Verizon signal. My sense is that it won't be a cheap circuit and would require a DSP...and expensive software programming. But I'm not an EE so I'll see what my engineers come up with. Maybe they can dream up a cheap way to do this with an external dongle of some sort.
     
  15. Ziggy86

    Ziggy86 Member

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    Jun 22, 2004
    Keep us posted, please.
     
  16. Ziggy86

    Ziggy86 Member

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    Jun 22, 2004
    How will they flatten the signal? To your house only or across the board?
     
  17. exdishguy

    exdishguy New Member

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    Apr 30, 2004
    I really don't know. It's a theory at this point. I don't know if they can do this at the ONT or have to do it at the CO.

    For now, the variable attenuators are doing a good job of "masking" the problem. I still see pixelization though so I'm going to keep pushing for an answer from both Tivo and Verizon.
     
  18. Ziggy86

    Ziggy86 Member

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    Jun 22, 2004
    How long does the pixellation last, a few seconds? Is it enough to make you not watch the channel and is it constant or a few time a day?
     
  19. sinanju

    sinanju Member

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    Jan 3, 2005
    For me, the issue affects 6 channels and is like an elderly relative -- it has good days and bad. When it's bad, some of those 6 channels are unwatchable for an entire day. More than once just this month I've had to reschedule recordings around a pixelation storm.
     
  20. NJRonbo

    NJRonbo New Member

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    Jun 3, 2005
    Since the attenuation I have seen little to no pixelation. I actually only see
    traces now and then.
     

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