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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. christoman

    christoman New Member

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    Feb 22, 2003
    Massachusetts
    Not sure if this belongs in this thread or not, but a number of months ago I took the advice of this thread and used attenuators to fix my pixelation problem on both Tivo HDs (I have FIOS). All of a sudden this week, a large number of channels just won't tune at all. A few will bounce between not tuning and very heavy pixelation (huge RS Uncorrected errors). As far as I know, nothing changed in terms of the overall environment (although something could have happened with FIOS outside my house). I have a tech coming over tomorrow. Any advice on how to direct him? Thanks.
     
  2. bivrak

    bivrak New Member

    15
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    Mar 19, 2008
    For the last few months, I've had good days and bad days with the same six channels as you. On the good days, the signal strength on those six channels approached 60%, while all other channels were at 100%. On the bad days, the signal strength would dip down to around 40%, while again, all the hundreds of other channels were at 100%.

    The last couple of days all of the six low frequency channels have looked great. The TiVo diagnostic screen is now reporting 100% signal strength on those six channels, which I never saw before, even on the days when they looked fine on my TV.

    I'm cautiously optimistic that Verizon finally figured out that THEY had a problem and have now fixed it.

    Sinanju, are you seeing the same thing in Rhode Island I'm seeing in Maryland? I hope so.
     
  3. Dmon4u

    Dmon4u Unresponsive User

    2,163
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    Jul 15, 2000
    PA
  4. JJA

    JJA Senior Citizen

    176
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    Feb 27, 2000
    Sarasota, FL
    count me as another successful repair to the pixelation problem. FIOS tech came out Saturday (I placed the service call Friday afternoon) and installed -13 which brought my SNR to 31. Picture great over the weekend. He also left me an assortment in the event I had to make some changes.
     
  5. NJRonbo

    NJRonbo New Member

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    Jun 3, 2005
    JJA,

    What exactly did they install? Was it attenuators?
     
  6. JJA

    JJA Senior Citizen

    176
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    Feb 27, 2000
    Sarasota, FL

    yes. a -10 and -3. ONe week and still no pixelation.
     
  7. jazmaan

    jazmaan New Member

    74
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    Aug 30, 2002
    I'd been running Verizon FIOS TV without any issues for about six weeks. Then a few days ago my HD local network stations started pixellating like crazy. NBCHD, CBSHD, FOXHD and ABCHD were unwatchable with broad swashes of pixellation every few seconds. I scanned these forums and elsewhere and tried turning off my Moca Router and I tried the reverse diplexer trick with no success.

    Then, in digging through my box of old electronic gadgets I stumbled upon an old Radio Shack "High Gain Cable TV Signal Amplifier with Adjustable Gain Control". I remembered that someone else had reported success with a discontinued Radio Shack variable attenuator. I wasn't sure my adjustable "Signal Amplifier" was the same thing. In fact I thought it was probably the exact opposite of what I needed, but out of desperation I gave it a try. At first it didn't help much. I tried turning the gain all the way down but it was still pixellating, although I thought I did see some very slight improvement.

    I was at the end of my rope. But as I contemplated my next move (a call to Verizon), a miracle happened. After about 5 minutes the pixellation completely disappeared! As I type this I've been watching for three hours without even a hint of pixellation on any channel! Hallelujah! The only down side is that the Radio Shack gadget needs to remain plugged in to the wall.
     
  8. BobCamp1

    BobCamp1 Active Member

    1,348
    10
    May 15, 2002
    Well, there are good AGCs and not-so-good AGCs. They obviously don't work well enough for some Verizon installations.

    Since this problem isn't as wide-spread for other cable companies, Verizon probably isn't helping.
     
  9. jazmaan

    jazmaan New Member

    74
    0
    Aug 30, 2002
    Even though my Radio Shack variable gain amplifier fix was working, I decided to call Verizon. They sent out a tech within 1 hour! I had to insist that he put an attenuator on the line. He was giving me all sorts of rationale for why an attenuator wouldn't work. But as soon as he put the attenuator on (-6db) the pixellation cleared up completely. He was astounded. "I guess I just learned something!" he said. He left me with a couple of extra attenuators of different strengths. Now everything is working fine.
     
  10. exdishguy

    exdishguy New Member

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    Apr 30, 2004
    I hope you have better luck than I did. My variable attenuators worked for a few days and then returned. I suspect the Verizon signal drifted some how....but who knows. I'm just sick of the whole thing. If Verizon cannot fix my service soon I'll keep TWC for now. But with TWC's neo-nazi limitations on fair-use that cripples MRV for all channels but my locals, I may just give up on Tivo altogether and use the stupid Motorola DVRs. Or maybe I'll wait for DirecTV to ship a new DirecTivo? ;)

    Check back in a few days if you don't mind and let us know if the attenuator is still working for you.
     
  11. jazmaan

    jazmaan New Member

    74
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    Aug 30, 2002
    I had a slight relapse and had to add one more -6db attenuator. Been pixellation free since then.
     
  12. NYHeel

    NYHeel Active Member

    1,915
    16
    Oct 7, 2003
    I've noticed some minor pixellation on ESPN HD 570. I put in a -6db attenuator but that didn't really do anything. I was at a 38 SNR and the -6db attenuator lowered me to 37. Is that normal? Also, does Home Depot sell these things? Anyone locally?
     
  13. bkdtv

    bkdtv New Member

    7,902
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    Jan 9, 2003
    DC Metro Area
    Most people need closer to 10-12dB, I think. I have one the earliest Motorola ONTs which output a very "hot signal" -- I require 16-18dB attenuation.

    Verizon FiOS installers have them, and you can order them online from Smarthome.com, but I'm not aware of any nationwide retailers that carry them.
     
  14. NYHeel

    NYHeel Active Member

    1,915
    16
    Oct 7, 2003
    I've got an old ONT as well although I do have a 6 line splitter on the line. I guess I'll just order from smarthome.com.
     
  15. Apr 1, 2009 #575 of 866
    subgenius37

    subgenius37 New Member

    14
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    Nov 15, 2008
    So I post a while ago about my experiences with attenuating to SNR 31/32, then finally using a low pass filter to remove most of the pixellation and I took off the attenuation because I thought it made the signal worse. I also mentioned that I had a multi-streaming cable card (only 1 card required for each box). Then I posted a follow up saying that I still had pixellation problems sporadically. After 2 more tech visits and 1 call trying to get them to fix the signal at the source. I ended up figuring out a fix that seems to be working 99% of the time.

    So with the multi-streaming cards you need 14 DB down and specifically 2 3DB down attenuators and 1 8 DB down attenuator. For whatever reason if you use a a 6DB and an 8DB or any other combo the attenuation changes based on channel. Sadly I can't explain it, and neither could the tech I described it to when I was looking for help. Now when I get pixellation it will be 1 or 2 little blips at most during a show that used to get wrecked with it.

    Hopefully this help others out there. I would have switched back off the multi-streaming cards but they were going to charge me a service fee to put in the new single streaming cards AND twice as much per month. So there you go.

    - subG
     
  16. Apr 2, 2009 #576 of 866
    richsadams

    richsadams Active Member

    8,893
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    Jan 4, 2003
    Nice follow-up and good info. Thanks! :up:
     
  17. Apr 2, 2009 #577 of 866
    fahooper

    fahooper New Member

    2
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    Mar 22, 2009
    I was at 37/38 SNR. When I put in a -20db attenuator my SNR went to 31/32. Haven't seen any problems since (4 days).
     
  18. Apr 9, 2009 #578 of 866
    panksdmz

    panksdmz New Member

    5
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    Nov 16, 2004
    got my FIOS video installed yesterday. One of the Tech was a Tivo user himself and was aware of the issue with the "hot signal" from ONT. He confirmed that a low-pass filter works better the the attenuators and asked me to try that before using the attenuators.

    He also told me that the problem is worse with the Morotola ONT's (i have a really old 610 series) and according to him the problem in pixelation was because of the signals coming from the router into the coax cable (i have my coax also feeding the new Actiontec router).

    Not sure how much of this is already known information.. wanted to share what i learnt.

    I'm not having any pixelation problems.... yet. Am at SNR 36. :confused:

    This thread was really useful :up:
     
  19. Apr 9, 2009 #579 of 866
    sinanju

    sinanju Member

    654
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    Jan 3, 2005
    The filter doesn't work better than the attenuators... they fix two different problems.
     
  20. cpettis

    cpettis New Member

    10
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    Aug 20, 2005
    I just went through the hassle of troubleshooting this issue, and thought I would share my solutions. Verizon came out to install the cable card in my second TIVO HD, and put 16 db of attenuators on both systems based on levels he read with a power meter. I had been running my TIVO HD in the living room with no attenuation and very rare pixelation. After the attenuators were installed, I noticed some channels with low power readings on both systems. I removed an attenuator on the new TIVO and all channels I checked were at 97% minimum, with most at 100%. SNR was between 36 and 38 db. My older system had issues with RC errors with no attenuators and low or no signal with an 8db attenuator installed. The only difference between the 2 systems installation was the new one was connected to the FIOS splitter with 100% quad shield RG6, while the older system had a 6 ft piece of RG58 in the line. I replaced the RG58 with RG6 quad shield and all the channels were pegged at 100%, but there were some RC errors on the problem channels. I added an 8 db attenuator and all channels were greater than 97%, with SNR's of 35 to 38 db and so far no RC errors. Based on past experience as an RF calibration technician, I think the RG58 cable, which dates back to the original cable installation, had a frequency response issue, but I don't have the equipment at home to prove this. I do think that Verizon's channel to channel power levels have some issues, but checking the complete signal pathway from the FIOS box to the TIVO can also help. I'm going to continue to monitor the DVR diagnostics when I see any pixelation issues, but for now it looks like I've solved my problems.
     

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