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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. bhaas

    bhaas New Member

    174
    0
    Aug 5, 2003
    MD

    really??? There's no catV running from the ONT to the router? I thought that the new installs had catV for the PC-destined IP and coax for the STB running out of the ONT- with no coax at the router.

    My install is the previous generation- all IP goes to the router, and the router splits the traffic onto coax or cat5.

    If there is cat5 between the ONT and router, and no coax at your router, then all PC-destined IP (ie internet) is on the cat5, and filtering will have no effect.
     
  2. Deanq4

    Deanq4 TiVo Lover!

    156
    0
    Sep 30, 2005
    Forest Grove OR
    ok, so after adding the diplexer like was stated above. I still get pixilation on a couple of channels, but is it less. I upped the attueters to 13db (from 12) and it gets the signal to 31 SNR, but still get pixilation on the ABCHD channel, it is better, but not great. If I bring it up to 15db it brings the signal down too low for most the channels. I think I may put things on hold till Fios changes and adds all the channels. i may then try to call verizon and have them look at it see it they can add something to fix it.
     
  3. thegeek

    thegeek New Member

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    Dec 16, 2002
    Wesley...
    Assuming you don't have any NIMs or Verizon STBs, yes there's no MoCA to filter. Not everybody is on an Actiontec. Some folks have the older D-Link router + NIMs.
     
  4. Gerhard

    Gerhard New Member

    231
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    Sep 29, 2002
    Yep, that would be me.

    As for the post above yours...

    I have had some pixelization after I put the splitters in, but it's been very light by comparion. Some of my channels are still VERY hot, even with 6dB of attenuation and the diplexer. (I'm thinking 8-10dB total...) Even when the signal strength is 70dB, the SNR is 33-35dB.

    So I either need to get the Verizon filter, and see if it works better... or add a little more attenuation.

    The difference is significant though...
     
  5. Wakefield33

    Wakefield33 New Member

    5
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    Apr 5, 2008
    Worked for me, thank you AbMagFab !:up:
     
  6. thegeek

    thegeek New Member

    230
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    Dec 16, 2002
    Wesley...
    FYI, the signal strength figure isn't measured in dB. It's more like the bars on a digital cell phone which is an arbitrary score based upon statistics on how many errors it's picking up and either correcting or not.
     
  7. Gerhard

    Gerhard New Member

    231
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    Sep 29, 2002
    Interesting. Every distortion analyzer I've ever used displays SNR as XX decibels.
     
  8. thegeek

    thegeek New Member

    230
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    Dec 16, 2002
    Wesley...
    SNR and "signal strength" are two different things.
     
  9. lrhorer

    lrhorer Active Member

    6,924
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    Aug 31, 2003
    San...
    OF course they are, which is why they also are measured in different units. S/N is the ratio of the signal level to the noise level, and is usually measured in dB. The signal level, sometimes called "signal strength". is a measure of the amount of signal (irrespective of the amount of noise), and can be measured in dBmV, dBm, dBW, Volts, mV, Watts, mW, etc. On CATV systems, the signal level is usually measured in dBmV. A signal level of +60dBmV is 1 Volt RMS across 75 ohms.
     
  10. moyekj

    moyekj Well-Known Member

    11,143
    31
    Jan 23, 2006
    Mission...
    I've never seen or heard of a Signal Strength reading on the Tivos greater than 100 (or less than 0 for that matter), so I assume it's some kind of percentage level unless the reading is truncated when > 100. I usually focus on SNR and RS corrected/uncorrected as more useful and well defined measurements.
     
  11. Deanq4

    Deanq4 TiVo Lover!

    156
    0
    Sep 30, 2005
    Forest Grove OR
    so I have seen a little bit of pixilation, not as bad as before. I was wondering if it was more the SNR or the MCoS thing?

    I went to watch one channel today and the signal was in the 40's and I could not watch it, so I need to remove some of the attueters, but then my SNR is going to be up in the 34-35 range.

    Tips?
     
  12. dforemsky

    dforemsky New Member

    43
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    Aug 6, 2003
    Pittsburgh, PA
    Can pixellation be caused by a bad cable card?

    I've been trying to nail down my pixellation issue for a while now and last night noticed that the signal strength was jumping all over the place with one card and steady with the other. I'm just not sure if this a symptom of a bad card, bad Tivo or bad ONT.

    I've tried different levels of attenuation, and even tried the backward diplexer idea last week. Attenuation helped on most of the channels, but the pixellation is stubborn on several of them (all of them in the "national" tier, mostly channels 144, 145 and 146 but probably more since those are my wife's favorite channels).

    I called Tivo, and they recommended attenuation to keep the signal strength between 93 and 95. The problem with that is that when I do that for the bad channels, other channels have low signal. However, now the signal seems to jump all over the place on the bad channels.

    I then called Verizon who tried a couple of things from their office that didn't help, then sent out a tech without any cable cards and had never even seen a Tivo. He left me some more attenuators and wished me luck.

    Should I ask for a new card? A low pass filter? A cancellation of my TivoHD subscription?

    thanks!
     
  13. Deanq4

    Deanq4 TiVo Lover!

    156
    0
    Sep 30, 2005
    Forest Grove OR
    It sounds like it is just trial and error with the attueters. I have gone from 3 up to 16 and back trying to find a happy medium. I just started the diplexer thing, and have had better luck, but have not had it on long. I am trying to find out now if the signal strengh is the important factor or is it more of the SNR thing.
     
  14. jcostom

    jcostom New Member

    28
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    Mar 6, 2002
    After adding a 20dB attenuator to our THD, nearly all of our pixelation problems vanished, with one exception - Food Network HD. That's been the problem child, and mostly at night, in particular. We do enjoy Next Food Network Star and the Challenges, so we wanted to get it cleared up.

    I added a diplexer, flipped around with the extra pole capped, and the pixelation seems to have vanished. It could just have been a lucky run of 15 minutes, but we'll see. For us, the combo of the reversed diplexer and a 20dB attenuator seems to be the magic combination.

    I about blew the minds of the guys in Radio Shaft when they found out what I was going to be doing with the diplexer. They also had that deer-in-the-headlights glare in their eyes when I mentioned the attenuators too. "So, an attenuator, that's like an amplifier, but backwards?" Yikes.
     
  15. litkaj

    litkaj Member

    257
    0
    Jun 5, 2007
    Exton, PA
    Hey, at least your's carries them. I went to the local crap shack last weekend looking for a diplexer and they didn't have those or the F-terminators.
     
  16. mulscully

    mulscully Member

    321
    0
    May 31, 2003
    Malvern, Pa
    had a similar issue, removed cable cards, blew them and the slot on the tivo with air, and reseated them.. rebooted and everything was fine...

    BTW no attenuators in my tivo 100% signal strenght and the SNR? in the mid to upper 30's.. Have attenuators, just havent had to use them yet...
     
  17. rifleman69

    rifleman69 Member

    853
    0
    Jan 6, 2005
    Oregon
    Have diplexor and I believe 12db's of attenuation here with no to very very little attenuation here. Used to have some problems with UHD, HDNet, and the HDTheater Discovery Channel (but not Discovery HD) every now and then but that's it. Keep fiddling around with it Deanq.
     
  18. bk_mallicote

    bk_mallicote New Member

    4
    0
    Jul 13, 2008
    Notification send out 7/22 to VZ employees. This issue would have to be resolved by a field technician.

    *Technical Description
    Some customers may report that their TiVo Series 3 or TiVo HD DVR is exhibiting severe tiling / pixelation / macroblocking on multiple channels.

    *Communication to Customer
    Apologize to the customer for the inconvenience and perform the below workaround.

    *Resolution/Workaround
    In order to workaround the tuner issue within TiVo, alter the RF power levels reaching the unit within the home. If multiple TiVo units are in place, RF power levels to each unit must be adjusted individually. Testing has shown that attenuating the signal to the TiVo to an approximate power level of -17.5dBmv digital (ch 55), then the tiling issue is alleviated.

    Procedure:
    Step 1. Access the TiVo diagnostic screen (TiVo, Messages & Settings, Account & System Information, Diagnostics)
    Step 2. Locate the Signal to Noise rating (SNR, provided in dB) Note: [Normal SNR should be in the 35-37dB range]
    Step 3. Attenuate the signal to the TiVo until the SNR is this screen reads in the 31-32dB range
    Step 4. Verify RF levels with Sunrise meter (should be in -17.5dBmv range for digital channel 55)
    Step 5. Check that channels for all subscribed services are funtioning (tunable) by the TiVo
    Step 6. Check that the channels that were exhibiting tiling are displaying normally.
     
  19. FiosUser

    FiosUser Member

    101
    0
    Nov 16, 2007
    Hip-hip-hooray!
     
  20. Deanq4

    Deanq4 TiVo Lover!

    156
    0
    Sep 30, 2005
    Forest Grove OR
    Update: Ok so I brought it down to 10 DB with the diplexer. Seems to be ok, at least I can deal with it. I see some pixialation, but not as bad as before. It may be the chanels now since we just did a huge channel change here and a couple of them are new. Plus some issues are on channels that I had before, but were fine.
     

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