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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. richsadams

    richsadams Active Member

    Jan 4, 2003
    The point of my post had nothing to do with the original topic and ongoing discussion in this thread (which is more than legitimate IMO), but was in reference to the proposition that something TiVo is doing or has done is so egregiously harmful to its owners that the only route of remedy is a class action lawsuit.
  2. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    The notion of a lawsuit is patently ludicrous in any event. All any manufacturer needs to to to prove themselves absent malice (and thus immune to damage litigation) is to show their device meets its published specifications, and that the device was being used with signals that did not meet those specs. A manufacturer is not liable in any state of which I am aware for any damages incurred from use of a device in an environment outside its published specs.
  3. exdishguy

    exdishguy New Member

    Apr 30, 2004
    Thanks for your informative posts. I've tried the low pass filter combined with the attenuators and I still have problems. Today, I finally managed to get an MCard installed and as you'd expect - it offered no improvement (other than on my wallet).

    I think item three on your list is definitely one of the culprits as I've had techs check signal integrity on a couple of different channels and they aren't consistent at all. That said, I've had the ONT changed already in case it wasn't modulating properly - but that didn't work either.

    Coupled with the above, my neighbor has a Moto DVR and he consistently sees pixelization on some of the same channels I do. That would infer that some channels have issues at the head end or that his Moto does in fact struggle with skewed levels too.

    I guess the bottom line is that this issue is multifaceted and Verizon is more culpable than Tivo (IMO) since their own equipment exhibits similar or the same problems as the Tivo's (albeit less frequently).

    I do wonder though - can I assume that Tivo could not field update their units to work with Fios because they are using can-tuners vs. silicon tuners so the sensitivity/tolerances cannot be dialed in with firmware?
  4. webin

    webin New Member

    Feb 13, 2008
    My immediate thought would be that the errors are being introduced at the head end.... lrhorer would tell us that a confabulator modulation card (or something beyond my comprehension :rolleyes:) is dirty or dying and needs replacement. V7Goose was very successful demonstrating identical symptoms and convincing Verizon to replace something in the headend office, which fixed his pixellation completely.
  5. wm2008

    wm2008 New Member

    Jan 2, 2009
    lrhorer, your misguided attempts to manipulate this thread are pathetic, and frankly your inability to consider anything other that Tivo perfection are laughable.

    You make comments and statements about "standards" yet you cannot produce them. Where are these "standards" lrhorer? Where? Why does a sunrise meter show completely different measurements than the Tivo? Why? My "attempts" to fix the problem are "all but deliberately designed to fail"? Really? Let's see, I've had Verizon AND Tivo involved. I've asked ALL OF THEM what can be done. I've had Verizon HERE. I've added the friggin attenuators. I've experimented with them. All of this with a Moto unit displaying ZERO PIXELATION.

    So READ MY LIPS - READ MY LIPS- READ MY LIPS to use your own language...

    I - and "Normal" customers not having the benefit of being the obvious right hand of the CATV gods like you are simply want the devices to work. I don't CARE if behind the scenes the Moto is dropping frames so long as it isn't visible and yields no unacceptable external evidence. I NEVER EVER EVER EVER EVER EVER (that enough for you?) said that the tuner could - or should - be designed for "infinite" variability. Only that it be designed for REASONABLE variability. Perhaps - just maybe - to the extent that Moto has done. Maybe to you that's unreasonable. Maybe you're just unreasonable.

    So, since you got personal and attacked, let me be more clear. I do not hold your "experience" or attitude in high regard. A Tivo HD which is from "your" engineering perspective (whatever that is) designed perfectly but which functions with flaws is an inferior product than one that has a "failure mode" (which ANY responsible and competent engineer should understand) yielding no critical failures.

    I don't own a sunrise meter. I am like thousands of other people who are forced to have others such as Verizon attempt to analyze this. Your position seems to be that every customer must be a CATV engineer, and that attempts to remediate this in any other way are pathetic and "designed to fail". Your attitude is SO incredibly Tivo biased that it is beyond description. Tivo themselves have been of zero value. None. Zilch. Their solution? Call Verizon. Well, I've done that. All the VZ equipment works perfectly.

    So, genius, what happens next? How about a scalable solution that allows for Tivo customes (you know, those people who are NOT CATV engineers but paid Tivo for a product and service) to get their products to work? Other than of course those people quitting their jobs and going back to school to become CATV engineers? Since the people who design, manufacture, distribute, sell and support the product (Tivo) have only one answer (Call Verizon) and since Verizon can't find anything wrong and correctly point to the fact that their equipment is functioning, what next?

    You're right. The title of this thread is not accurate. It ought to be titled "Tivo pixelation issues - try some attenuators and if they don't work screw you".
  6. JustAllie

    JustAllie Number crunchin'

    Jan 4, 2002
    Arlington, VA
    Between all the arguing, has anyone come up with a reliable fix for this problem? Should I try the attenuators?

    18 pages of back and forth are a lot to wade through.

    My problem is periodic pixelization on some SD channels. (I don't watch the HD channels that much, so I can't say what they're like.) Most recently I've noticed it on CBS and NBC. It doesn't seem to be my Series3 hard drive that's at fault, because when I rewind, the pixelization occurs in the exact same spot -- so presumably it's in the signal from FiOS, or an issue with the CableCARDs, or something.

    I have some attenuators from SmartHome -- which one(s) should I try first?
  7. bicker

    bicker bUU

    Nov 9, 2003
    Let's be clear about something. lrhorer and I rarely agree with each other -- and indeed there are many aspects of this very issue that lrhorer and I disagree about, however I think it is safe to say that we both agree that TiVo is not unequivocally in the wrong here, as you're trying to assert.

    As I mentioned before, since Motorola found a way to, it is likely that TiVo could have made their product more robust, with regard to this failure mode. Beyond that, in general, TiVo could have done a much better job with regard to making the TiVo S3 and HD more robust -- there are other instances of lack-of-robustness in TiVo's designs, that we've discussed over the years.

    However, they had no obligation to do so, and are not necessarily wrong for not doing so. They'll lose some sales and incur some other costs, perhaps, for not having made their product more robust, but for all we know it would have cost them more to engineer the product to reduce the extent to which the failure mode is noticeable. There is no minimum level of robustness that a CE manufacturer must achieve in their designs, and to assert that there is shows a distinct lack of understanding of the mass-market consumer marketplace, just like asserting that there is no way to design more robustness into the product (i.e., making the failure mode less noticeable by end-users) shows a distinct lack of understanding of systems engineering.

    To be fair, I think you got personal with folks in this thread who you disagreed with long before lrhorer got person with you. I think you're better off quitting that issue before you fall too much further behind, since his responses to you are substantially just response-in-kind, and therefore perfectly justifiable as such.

    You are better off quitting this issue, too, before you fall too much further behind. Your attitude is "so incredibly" anti-TiVo biased. Balance, unremarkably, is found somewhere between your extreme (and therefore indefensible) position and his extreme (and therefore indefensible) position: TiVo isn't "right"; and TiVo isn't "wrong".
  8. Dmon4u

    Dmon4u Unresponsive User

    Jul 15, 2000
    Cutting through the chaff around here,

    I had good results starting with 16 db (a 10 and a 6) and then adjusting up or down from there.
  9. thecrave

    thecrave New Member

    Dec 2, 2004
    Buffalo, NY
    I've had good results with a diplexer (no attenuators) thus far.
  10. NJRonbo

    NJRonbo New Member

    Jun 3, 2005
    I thought I had posted this here previously....maybe I did, maybe not.

    I wrote Tivo corporate shortly before Christmas. Received a call from
    a Tech located at their corporate office.

    Basically, Tivo has been aware of this problem for quite some time but
    claim there is little they can do to modify their players without the chance
    of making them unusable on cable systems. In other words, if they try to
    correct the problem for one then it affects the other.

    I have no knowledge of whether they were being truthful or not, but they
    did at least call me back and not only explain their situation but try to help
    me correct it. They also extended my trial period for an extra month.

    I used a -10db attenuator and also (per Tivo's suggestion) added a short
    coax patch cord with barrel connector to slightly bring the signal down lower.

    Thus far, the pixelation is totally gone.
  11. substance12

    substance12 Member

    Feb 6, 2008
    thanks for the update. can you post the address you mailed to them?

    also, what do you mean by a coax patch cord?
  12. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    A head-end issue is the more likely cause in this scenario, although the latter is possible.

    It is suggestive of that, but hardly conclusive. It could even be a case of two bad DVRs, unlikely as that is.

    I do wonder though - can I assume that Tivo could not field update their units to work with Fios because they are using can-tuners vs. silicon tuners so the sensitivity/tolerances cannot be dialed in with firmware?[/QUOTE]
    I'm not sure what the hardware in the TiVo HD is, but even the S3's can-tuners could be replaced. The bottom line is the sensitivity of the TiVo is just fine. I had intended to get some attenuators the last couple of days to investigate the Tivo's minimum sensitivity, but other things have intervened.
  13. NJRonbo

    NJRonbo New Member

    Jun 3, 2005
    Thomas S. Rogers, Tivo CEO
    2160 Gold Street
    P.O. Box 2160
    Alviso, CA 95002-2160

    A coax patch cord is a 1-2' piece of coax that you can buy at Radio Shack.

    The idea is not to over attenuate or you will lose signal on some channels.

    For that reason, the Tivo tech said he generally recommends using a -10db
    attenuator combined with a small patch cord with a barrel connector to bring
    the signal down ever so slightly more without over doing it.

    For me it worked great. The -10db attenuator still resulted in fleeting glimpses
    of pixelation that lasted seconds at a time. Really not a big deal, but once I added
    the additional piece of coax and the connector (female to female) it totally removed
    any random pixelation.

    Now, from what I hear, each home is different. Some homes need more
    attenuation. It's even recommended that you look at the Tivo menu and make
    certain that you stay within certain signal parameters (as probably discussed
    in this thread).

    I don't have the time to sit and fiddle with stuff. I did this blindly, hoping to
    throw on an attenuator and get results. So far, it has worked.
  14. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    Feel free to laugh. All of my TiVos work perfectly well WRT this issue, as do the vast majority of Tivos out there. Frankly, I no longer care in the least about yours. I will, however, continue to try to help those who actually want their Tivos to work, which clearly you do not.

    I produced them once. I'm not going to reproduce them again. It's clear to me you almost certainly do not wish to see them, but on the odd chance you do, look up FCC Regulations CFR 47 part 76, wherein CATV Proof of Performance specifications for CATV systems are spelled out.

    By the way, specifically stated in those regulations is the requirement "...maximum level must not overload subscriber's equipment. "

    Please feel free to go argue with the FCC over that, as you have done ad nauseum in this thread.

    Not being there, I cannot say for certain. The values reported by you , however, were horrible, and even a 30 mile long CATV cascade should have much better S/N than that. Given the FIOS cascade is 1 amp deep, if the S/N is really that bad, then there is something horribly wrong with the FIOS system. That said, there are plenty of possible causes of the situation.

    On Tuesday, I had Time Warner come out to diagnose a problem we were having locally. Now, the problem was known to be happening to TiVos city wide, so the truck roll was not really necessary, but rather than muddy the water, I allowed them to come to the house to do proper testing. Time Warner also employs Sunrise test sets (actually, so do we, but different ones), and both techs had Sunrise meters with them. Testing the very same drop, the two sets showed more than a 6 DB difference in level on all channels. Independent verification showed one of the meters was incorrect, the other accurate. Since the problem was entirely unrelated to levels, or indeed to signal quality at all, it really did not matter, but the fact I was able to prove to the techs the problem was not with the TiVos prevented them from blaming them, as they tried to do at first.

    Not that it is actually relevant to this case, but Scientific Atlanta DVRs did not have the problem. Clearly TiVo was at fault for poor design, right? Wrong. A number of CSRs had made a systematic error in setting up TiVo accounts which did not become evident until the Tuning Adapter was deployed. I'm not saying anything like this is at issue on FIOS systems, but the simple fact is a working device of different type / design is not diagnostic of very much in this situation.

    Merely getting someone involved, as you put it, isn't going to help. To the best of my ability to tell, no one with which you have dealt has had the resources, either mental or physical, to fix the problem. The very fact it isn't fixed bears this out.

    Asking a moron for advice is hardly the best way to obtain a solution. How many of them were engineers? Why is it when you do ask an engineer what can be done, you completely ignore his instructions?

    Whoopie. You did not ask them the pertinent questions I told you to ask. You did not report any significant feedback. Apparently you did not have them measure the level of the MoCa carrier or other carriers above 1000 MHz. Instead of actually asking what the levels were and writing them down, you apparently just took his word for it that "everything is fine". I can't count the number of times technicians have told that lie to me, including from many who worked for me. It doesn't take a genius to know many people will tell a facile lie in order to get out of doing any extra work. It also doesn't take a genius to know someone may be mistaken. The only way to know is to double-check the work, and that means having him read the numbers and writing it down.

    Which I already expressly told you is doing little other than farting in the wind. Why did you do this? What purpose did it serve? Why do you persist in intentionally doing things that have very little chance of succeeding and then blaming TiVo for your own malfeasance? A professional engineer whose former field was the very one in question has told you what to do. Until you do it, you have no cause to blame TiVo, Verizon, or anyone else.

    Oh, we didn't know that. Obviously, that solves the problem, and so you're happy.

    Apparently not. Apparently you just want to crow about how the Motorola works and the Tivo doesn't. Otherwise, you would have taken my advice.

    I've already shown the Tivo has a more than 17dB window, which is more than respectable: it is a factor of more than 25 from the lowest to the highest level, and quite a bit wider than an average TV set. I never said anything about the Motorola dropping frames, or anything else. The Motorola is not relevant.

    Motorola hasn't done it, as evidenced by your post. The S/N is worse, and its ability to handle lower - but not apparently low - signal levels is by your own evidence inferior to the Tivo's. That it works for you does not even begin to mean it has a wider tolerance range than the Tivo. More importantly, you keep harping on the sensitivity and high signal tolerance of the sets, when it very likely has little to do with the situation. I suspect the Tivo could be re-designed to handle a 50 watt input signal and it would make little difference.

    There is no such thing as perfect design, and the Tivo is certainly not perfect. The Tivo meets and exceeds industry standard specifications for handling signal levels, both high and low. That is all it can reasonably be required to do WRT this issue. You can rant, rave, and squeal all you want, and it will not change the fact. That, or you can take my advice and have the situation fixed in a matter of a couple of days.

    The only bias in my attitude is a (or was) a genuine desire to fix the situation. Calling Tivo is never going to help with this problem, ever. Calling them is a waste of time. It's not their problem, it never was their problem, and it will never be their problem. (Caveat: I don't recall your saying the TiVo had been replaced. This all could be the result of having a bad TiVo, although I seriously doubt it.) You can rant and rave at them all day long, and it won't solve your problem. You could force the company into bankruptcy,and it won't solve your problem. You could hold the senior staff of TiVo hostage and it won't solve your problem. The one and only thing that will solve your problem is to bring the signals at the back of the Tivo into line with industry standards. Period. This can only be done by someone on site at the source of the problem, which seems likely to be at your house. The most likely means of achieving the end are getting rid of OOB carriers and balancing the signal. If that still doesn't help, an investigation of what may be extremely low S/N issues on the FIOS plant may be in order. Once all of this has been addressed, clearing the FIOS plant of all prospective issues, then it may be appropriate to talk about TiVo's engineering, but even then only after the Tivo has been replaced.

    I am not quite a genius. My IQ tests at slightly below genius level. It is more than sufficient to this task, however.

    How about you follow my advice? That has a good chance of working.

    You (and they) are already paying Verizon a good little chunk of change for engineering services. Avail yourself of them.

    By your own testimony, the FIOS equipment isn't working. A S/N as low as the one your reported is completely out of line. What's more, you did not report back on the actual levels, flatness, or magnitude of OOB carriers. Without that data, no one can claim the FIOS signal is properly operational.

    What can I do to get through to you? Despite my explicit instructions to the contrary, you insisted on @#%#ing around with attenuators , when they had little chance of fixing the problem. You were told this, several times. Now you are complaining because p*ssing on the spark plug didn't make the engine run. "Screw You", is starting to seem very much like the appropriate response to someone who asks for advice, refuses to follow it, and then whines about the fact his refusal to follow that advice results in a poor outcome.
  15. lrhorer

    lrhorer Active Member

    Aug 31, 2003
    A 2' patch cord is not going to significantly affect signals (unless it is bad). The loss of a typical RG-6 cable is less than 0.02dB at 50 MHz and less than 0.14 dB at 1 GHz. A 20 meter patch cord will definitely have an affect on the signal, but not necessarily the desired one. If the system tilt is very positive and the level somewhat high, then a moderately long piece of coax will help. If the system tilt is negative, then the last thing one should add is additional cable, although once again a jumper less than 3 meters long is not going to have any significant effect.

    Which will easily happen if the high frequencies are lower than the low frequencies and an additional unnecessary piece of cable is added to the equation. Variations of 1 dB or less are generally not significant.

    You don't have to hear very well to know this. First of all, reportedly the output level varies somewhat with the model of ONT installed. Secondly, some homes have only 1 TV, while others have 4 or more. At the highest frequencies on the FIOS lineup, a 2-way splitter will lose about 4.5 dB, while a 4-way splitter will lose almost 9 dB, and an 8-way splitter will lose over 13 dB. On top of that, some houses are large (one with more than 4 TV sets probably will be), while others are quite small. This means the length of the drops will vary quite a bit. At 50 MHz, the RG-6 cable will attenuate the signal by about .05 dB / meter, while at 1000 MHz, it attenuates about 0.24 dB / meter. Thus, a more or less typical 20 meter drop will attenuate the low end about 1 dB and the high end about 4.8 dB. Increaseing or decreasing the drop length will change the losses correspondingly, resulting in higher or lower levels at the receiver.

    Which is OK-ish. It's a quick, simple, and inexpensive thing to try. I would not rate its odds of success terribly high, but if it worked in your case, then I'm happy for your luck. It is very much like shooting rabbits in comeplete darkness. The fact rabbit are common means it is not an entirely futile effort, but eve in the most rabbit-infested field, actually hitting one is not too terribly likely.
  16. webin

    webin New Member

    Feb 13, 2008
    All this talk lately has re-motivated me to do some analysis of my fios signal, and I've come up with a question.

    I looked at 45 HD channels in DVR Diagnostics, all with Tuner 0 (which seems to produce more quality issues than the other). I found that channels with a lower frequency have higher signal strength and SNR (I also found SNR and Str seem to be almost perfectly linked). I seem to have the most picture quality issues on the local HD channels, which are on frequencies 507MHz, 513MHz, and 519MHz. I also didn't find any channels on frequencies in the 400-500MHz range.

    Thinking about out-of-band carries and such.... can anyone think of a reason Verizon hasn't put channels on frequencies in this range? (Conversely, can anyone find a channel that IS in that range?) I'm wondering if there's a logical connection between that gap in frequencies, and my problem channels being the very next frequencies used. I'm wondering if there's some non-channel signal utilizing that range that's interfering with the cosmic karma.

    On a separate (but equal) note, I have found that MOST of my RS Corrected and RS Uncorrected errors are occurring on the problematic local HD channels, as would be expected with signal issues. I was watching channel 506 (CBS) for a while in particular, and found my signal strength was more variable than other channels... even dropping momentarily to 0 from time to time. I doubt this is related to my attenuation (all tests were with 6dB attenuation), but will have to decide if it's a head-end issue.

    One last editors note: My use of the term "problematic" is relative. A problematic channel for me is still very watchable.
  17. richsadams

    richsadams Active Member

    Jan 4, 2003
    Good questions and observations. I don't have any answers but I'm also interested in hearing from others about your findings.

    Thinking about issues with local HD channels, would it be worthwhile to try OTA to see how things look? I had an indoor Terk antenna connected to our Series3 for a while and the local network HD channel's PQ was remarkably good...as good as Comcast's. I think you're within 10 miles of the local antenna array and if you're still having problems I'm wondering if it might be worth a try? It wouldn't solve the VZ issues of course, but you'd at least have decent quality recordings until they are resolved.

    That said, I saw minor pixelization/macorblocking once in a while even with OTA broadcasts, so I don't think it can ever be perfect.
  18. JustAllie

    JustAllie Number crunchin'

    Jan 4, 2002
    Arlington, VA
    My pixelization is very sporadic, so I just started with a -10 dB and will see how that goes. Thanks very much for the response.

    It turns out that I already have a short patch cord between the attenuator and the TiVo, because I split the signal between my TiVo Series3 and my housemate's TiVo Series2 in this particular room. So I am probably already attenuating the signal by splitting it.
  19. necrotaur

    necrotaur New Member

    Feb 25, 2008

    I have had the two THD's working fine for a while now, but noticed a couple issues recently:

    QAM channels at 195 MHz (ESPNNEWS HD & Starz4Kids) are horribly pixelating and are unwatchable. I have not watched these before, so I don't know if its been an issue

    QAM Channels at 201 MHz (ESNPU HD & HSN HD) don't even get a signal.

    I have done everything, including adjusting / removing attenuation removing my NIM100's and diplexers (which were properly terminated, BTW) and checking the connections. Is anyone else in VHO8 seeing these issues? I find it hard to see that these two specific frequencies are having issues, and it being directly related to the attenuation issue.

    Adjusting the attenuation affects any channel except the ones on 195, and I never see a signal on 201.

    If anyone can check what is going on and post, I would appreciate it.


  20. sinanju

    sinanju Active Member

    Jan 3, 2005
    Those channels are not on those frequencies in my neck of the woods. You're going to have to give people an idea of where you are if you want someone to compare their experience to yours.

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