Bad OTA reception with HR10-250

Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by summerall, May 14, 2007.

  1. summerall

    summerall New Member

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    Aug 5, 2001
    columbia, sc

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    I mounted an antenna at the highest peak in my attic to receive OTA high def channels with my HR10-250. Sometimes reception works and the HD channels record with no problems, BUT more freqently I get audio breakups, pixelation, and sometimes the shows don't record at all. Case in point, tonight Heros didn't even record! I checked my reception levels via the Settings menu and the levels for NBC jump very dramatically 20's to 65's. However on FOX the reception stays at around 80-90 and I still get audio breakups sometimes.

    My questions are:

    Do HR10-250 generally have bad OTA reception?

    How can I improve my OTA reception without doing anything else to the antenna? It's at the highest peak already.

    Should I switch to another HD DTV receiver? Do other receivers provide better OTA reception?

    Thanks
     
  2. turbobuick86

    turbobuick86 Member

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    May 2, 2002
    Without doing anything else to the antenna? Try moving your house closer to the transmitters. ;)

    If you are aimed correctly and you are sure they are transmitting a decent signal, then either need to improve your antenna/reception or ask your neighbors if they are having problems too. When you start going through walls to get reception, it's not hard to understand if it's spotty at best.
     
  3. Matt L

    Matt L Member

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    Aug 13, 2000
    Flushing, MI
    An attic antenna is only slightly better than an indoor antenna. Plus, in your case it sounds like you have a multipath problem. Not knowing how far you are from the towers and your topography it's hard to pinpoint your problem.

    You might try turning the antenna a bit one way or the other. I'll assume you know the front of the antenna from the back, though a number of people have not.
     
  4. JimSpence

    JimSpence Just hangin'

    30,919
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    Sep 19, 2001
    Binghamton, NY
    The OTA tuner in the HR10 isn't as good as the one in my HTL-HD receiver. Of the four stations here, the HR10 can get one fairly reliably. The HTL gets them all. The HR20 is reportedly better.
     
  5. Indiana627

    Indiana627 Member

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    Jan 24, 2003
    Vestal, NY
  6. TyroneShoes

    TyroneShoes HD evangelist

    3,604
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    Sep 6, 2004
    The HR10 does not technically "generally have bad OTA reception", but I can see how folks might assume that. The reality is that it does not reject multipath interference as well as most garden-variety tuners do, and it does not tolerate overly-strong signals. Its state of art is a few years behind most HDTV tuners. So the problem will only affect you if you are in a reflective environment, or the signal is too strong.

    Saying that the HR10's tuners have "bad reception" would make one think it would not work well even in a non-reflective environment, but that is absolutely not the case. For instance, I have a $0.79 piece of twinlead taped to a window as my antenna, and all 3 of my HR10s have perfect reception, 24/7/365. But then I have pretty good line of sight, and am only 20 miles from a single tower cluster, so life for me is good using the HR10s, and their reception is perfect.

    The solution for you is probably to begin with the best antenna system you can engineer for the precise requirements of your location, and mount it in the best possible location, which I'm afraid will never be inside an attic. Higher is generally better, but it is not simply a matter of height alone. We can give you all the guidance necessary to do that, in fact all you need to know is right here on this forum.

    Other tuners can indeed be better in such marginal areas. You will generally have better luck with reception using the HR20 or something else if you are affected by multipath, but the tradeoffs are very steep. Still, if you engineer a proper antenna system and still get "bad reception" on the HR10 while your HDTV tuner works OK, that might be a useful option. Or, if you don't want to bother with that, or are physically prevented from that due to location, the HR20 is one option that might work better. In many locations it will get the local OTAs even without an antenna (through the sat directly).
     
  7. lightguy48

    lightguy48 New Member

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    May 17, 2004
    Waco, TX
    I had remarkbly better improvement in signal quality by moving the antenna from my attic to the chimney on our house. You might also look into an antenna that has better performance such as a Winegard Squareshooter.

    Also, you didn't say if you were running an amplifier or not. If you are running one is it HDTV ready? Older amplifiers may not handle the peak power of an HD signal like the newer ones will.
     
  8. TyroneShoes

    TyroneShoes HD evangelist

    3,604
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    Sep 6, 2004
    Where in the world did you ever get that idea?

    There are differences between analog and digital carriers, and there is a way to look at measurements of either type of carrier as "peak power", but the "peak power" as well as the RMS power of 8VSB carriers is typically actually much lower than that of NTSC signals as received, so "older" amps are no different than "newer" amps as far as feeding them with an input of a proper level and them being able to handle it.

    The attached spectrum display shows a typical hybrid cable system, with analog carriers below 500 MHz and digital carriers above 500 MHz. You can easily see that the peaks of the analog carriers hover a good 10-15 dB above the typical level of the digital carriers. OTA is a little different, but still very much the same situation. The coverage of 8VSB is designed to emulate the coverage of the NTSC signal it will be replacing, and generally speaking the digital carriers are typically not broadcast at higher power than those analog signals. If they were, there would be tremendous interference issues between adjacent markets since they all share the same spectrum to a large extent.

    Consumer amps typically want to see an input level of about 0 to +8 dBmV, whether the signal is NTSC or 8VSB, which makes pretty much all garden-variety amps interchangeable for either NTSC or 8VSB distribution. And actually, you can feed a 8VSB signal at a significantly lower level (10-15 dB lower) than NTSC without any penalty to PQ, because there is no noise degradation to worry about, which is exactly why it's done that way as seen in the attached diagram.

    IOW, if it works for NTSC, it will probably work even better for 8VSB. "Newer" amps are not designed to handle increased peak power compared to "older" amps, because there is no reason for them to be designed that way. The amp can't tell, or care, what type of signal it is amplifying. As long as it's in the window of operation (and 8VSB and NTSC signals generally fall into that same window) everything will work out just fine.
     

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  9. coachO

    coachO New Member

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    Nov 25, 2004
    near...
    I learn something every time I read one of Tyroneshoes posts. Thanks.
     
  10. TyroneShoes

    TyroneShoes HD evangelist

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    Sep 6, 2004
    Thanks. It's gratifying to see that you understand the spirit in which I post, which is usually to clarify and never (well, ok, rarely then) to chide. :D

    Here is an expanded version of the earlier pic (I had trouble attaching this one yesterday), this time showing just a few carriers around the transition from analog to digital. Notice how the analog carriers have steep spikes for video, chroma, and audio, while the carriers for QAM have flat-topped "dispersed" energy carriers that fill each 6 MHz channel evenly from band-edge to band-edge. That proves at least that "peak power" is significantly higher for analog carriers.

    The single analog channel (71) just below the transition to digital is a little misleading, as it appears with only a clean video carrier (no audio carrier or chroma modulation), While 69 and 70 are normally-modulated analog, and 72, 73, and 74 are digital.
     

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  11. lightguy48

    lightguy48 New Member

    37
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    May 17, 2004
    Waco, TX
    Maybe what I saw was someone's marketing term on a product.

    But I know for a fact that not all RF receive amplifiers are designed the same. Depending on the type of FET design in the unit it can affect SNR and also the ability to withstand signal overloading.

    I apologize for that statement in my message.
     
  12. ggekko12

    ggekko12 New Member

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    Mar 12, 2007
    HI, I tried doing a search to see if this was discussed before, so I apologize if this has been asked before. Appreciate any insight or the place to see it already addressed.

    I bought a HR10-250 on Ebay and crossed my fingers it would be in decent working condition. I have 2 TIVOs and needed this one for my brand new Toshiba-62" 1080p Rear-Projection DLP HDTV-62HM196. I went all out and got top of the line Monster HDTV cables etc. Everything works great except that I do notice that occassionally the picture will distort in 2 instanes, action is too fast or there is too much of a busy picture. Small blotches appear for mili-seconds and then the picture normally returns to normal. Take for example, the early scene in Casino Royale (taped the HD PPV version) where they are jumping from crane to crane, the action is too fast for the picture. Then there are chase scenes thru crowds where too many people with different colors causes this issue. Any ideas if this is the HDMI issue or is this just something I need to live with given the size of the TV? Thanks
     
  13. annenoe

    annenoe He's a Smooth Fox

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    Oct 19, 2003
    Mountain...
    I can tell you from personal experience that I my reception is less with the HR10-250 compared to my TV. I just split my single indoor antenna to feed both the HR10 and the TV. Last night, I was watching something thru the HR10, it started to stutter, I immediately jumped over to live TV and it was rock solid - back to the HR10 - pixellating. From the same antenna.

    I can look at signal strength thru my HR10 and it will be fluctuating. I switch to the live TV feed and my signal is solid. Granted these are two different methods, but judging only by stability (not strength), the TV signal doesn't bounce.
     
  14. JimSpence

    JimSpence Just hangin'

    30,919
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    Sep 19, 2001
    Binghamton, NY
    What you are seeing are motion artifacts caused by overcompression of the signal at the source. And, as you suspected, the size of the TV exacerbates the problem. You can alleviate this affect a little by having your new TV calibrated. Get the AVIA or Digital Essentials calibration DVD. In the meantime, turn down the brightness, contrast and sharpness settings on the TV. They are set at max from the factory.

    BTW, you wasted your money by buying expensive cables.
     
  15. mschoaf

    mschoaf New Member

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    Nov 16, 2003
    Chicagoland
    I had an amazingly similar problem earlier this year...with a twist. Mine was with ABC. While all other stations were rock solid at 85+, ABC on 1 tuner would be in the high 80's while the other tuner would bounce around as you describe. And, depending on how recordings went, if my show tried to record an ABC show from the bad tuner, it wouldn't.

    So, as mentioned earlier in this thread, I put a signal booster in line and all is working fine now. I had an older one from Radio Shack lying around that had an adjustable gain, but I haven't seen anything like that lately.
     
  16. TyroneShoes

    TyroneShoes HD evangelist

    3,604
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    Sep 6, 2004
    You have absolutely no reason to apologize. We're all about inclusion over here at TC. You did nothing at all wrong. But it does appear that you might have been slightly mislead through no fault of your own, which again there is no disgrace in (otherwise the entire 2002 congress would be disgraced...oh yeah, I guess they are, not for being mislead, but for not correcting or learning from their mistakes).

    You are right about not all amps being the same, but virtually all consumer amps are designed to operate within a similar window of operation, and since ATSC and NTSC signals are broadcast at similar power levels, even if the amps were designed differently regarding their overload level it would not make a real difference which class of RF signals they were amplifying, which is why amp design does not distinguish between ATSC and NTSC as might have been implied. HPAs/LNAs for sats tend to have a tighter oscillator for digital signals because jitter is an impairment that digital signals are more susceptible to, but in the world of consumer RF amplifiers, that is not an issue.

    It's also true that some amps have a better or worse noise figure and that some have slightly more headroom, but as a rule amps are not designed differently for ATSC vs. NTSC as was implied earlier. As it turns out, legacy analog design parameters more than meet the requirements of ATSC, so amplifier design has had no need to change to accomodate it, and hasn't.

    A higher noise figure can be an issue if you are amplifying analog signals, but that would tend to make the cheaper amps actually MORE suitable for ATSC, since a higher noise figure has somewhat negligible affect on digital signals. Likewise, the kinds of distortion products caused by RF overload, such as cross-modulation, composite triple beat, and second and third order harmonic products will deteriorate NTSC signals long before they become a problem for 8VSB or QAM signals, even if the signals are amplified by the same amp at the same level, even at the same time.
     

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