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Hr20-700 ota

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by wilbur_the_goose, Feb 25, 2012.

  1. wilbur_the_goose

    wilbur_the_goose Hall Of Fame

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    Bought a new TV last week and hooked up my antenna directly to the TV. Wow. I think I now have 10 more channels (OTA) than I had thru the HR20-700.

    Granted, the HR is old, but come on. My new TV is a sub $400 Sony 40". Is the D* equip really that bad?
     
  2. Go Beavs

    Go Beavs Hall Of Fame

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    The HR20 relies on DIRECTV's guide data to know what OTA channels are available and at what RF channel to find them, it doesn't scan for channels like a TV will. It has been stated in these forums that DIRECTV isn't adding any more OTA sub channels to their guide data due to space issues.

    The new DIRECTV TiVo and the HR34 can scan for channels but if it finds channels that aren't in the guide data, you won't have any program info but at least you can tune to them.
     
  3. wilbur_the_goose

    wilbur_the_goose Hall Of Fame

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    Actually many of the "new" channels were in rhe guide but the tuner was too poor to pick them up.
     
  4. litzdog911

    litzdog911 Well-Known Member

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    Mill Creek, WA
    The AM21 ATSC tuner technology is pretty dated compared to modern HDTV tuners. And its feeding two internal tuners, not just one like your TV.
     
  5. TomCat

    TomCat Broadcast Engineer

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    First, the HR20 became available in August 2007 so the design is more than 4 1/2 years old. I can attest from professional experience that the improvement of ATSC tuners has probably as rapid a path as any consumer technology out there. In 2004 you almost absolutely had to have line of sight and an outdoor antenna to get very many channels, and today often a paperclip attached to the RF connector will get you most channels. The HR20 tuner is about 100 in dog years, so a new TV will run rings around it for OTA reception.

    Second, I think the older HRs still use the database of channels that is sent via DTV rather than creating its own database of channels via PSIP, which is what all modern TVs do during a channel scan. The PSIP scan will be very accurate and completely up to date, while the DTV method is far from accurate and far from up to date.

    That fact would invalidate any head-to-head comparison of the tuners based on sheer channel numbers, although we know that the HR20 tuner is old enough for it to not be a fair fight in the first place.
     
  6. TomCat

    TomCat Broadcast Engineer

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    You probably recall that the HR20 (what the OP has) does not use the AM21, but an older built-in tuner.

    Feeding more than one tuner is not in any way a handicap for digital reception, especially since the AM21 is an active device which very likely has RF unity gain to both tuners.

    The significant improvements in ATSC tuners are basically improvements in active EQ which means that the tuner can pick out primary signals and minimize the levels of reflected signals in a multipath-rich environment; possibly a bit of noise figure improvement as well, which really doesn't mean much. In an environment where multipath is relatively low, any old garden-variety ATSC tuner since the beginning will pick up pretty much anything, including those in DVRs older than the HR20 and the HR10-250. Once multipath levels are high enough, the newer tuners will prevail soundly outperforming the older tuners. Of course the PQ in all cases will be identical.
     
  7. NR4P

    NR4P Dad

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    Actually older technology than that. Looking at an HR20-700 here with manufacturing date 09/2006. So production was 2006 and likely a 2005 design.

    The AM21/AM21N's are much better than the HR20's for OTA.
     
  8. allenn

    allenn Icon

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    Georgia
    I wish the AM21 did that too. I do not need program data, but it would be nice to have all the Atlanta sub-channels in one place.
     
  9. gcd0865

    gcd0865 Legend

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    The AM21N, when paired with the new HR34 main receiver, supplements the zip code-produced channel listing with additional stations detected by scanning. The additional scanned stations can be tuned, although no guide data appears for the scanned stations ("Regular Programming" appears for those stations instead).
     
  10. wilbur_the_goose

    wilbur_the_goose Hall Of Fame

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    I guess I should've said "it's amazing how much better the OTA receiver technology has become since 2006".
     

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