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Local Reception

Discussion in 'Local Reception' started by kevinturcotte, Jun 12, 2010.

  1. kevinturcotte

    kevinturcotte New Member

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    Dec 19, 2006
    Outside...
    I'm trying to pick up a specific channel. I've attached my chart from tvfool.com I'm using a Channel Master 4228HD antenna http://www.crutchfield.com/p_6594228HD/Channel-Master-4228HD.html?tp=3261. I'm playing with it, and right now I can get channel 10 in perfect. As far as alignment goes, if I'm getting 10, shouldn't I also be getting 23 in as well? Is the fact that I'm getting 100% on 10 and 0 on 23 an indication that I'm NOT going to get 23? Would a different antenna maybe have better results, or should I just stop trying at this point?
    And yes, Directv does provide my locals in HD, but they don't provide them all, and the ones that they do, I'd like a backup for.
     
  2. Scott in FL

    Scott in FL Godfather

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    Mar 18, 2008
    The gain for that antenna on channel 10 is about 5 dB. On channel 23 the gain is 11.6 dB. So about 6.6 dB more gain on channel 23.

    TVFool shows channel 23 about 6 dB lower, so only considering power at the antenna terminals they're about even.

    Coax loss and the noise factor of your first RF stage are going to favor channel 10. But I think the real culprit is the 2edge path for both. That's a tough path and throws all this math out the window. Multipath and diffraction are going to play significant roles, making prediction difficult.
     
  3. kevinturcotte

    kevinturcotte New Member

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    I don't think there's too much coax loss. There's maybe 50 feet between the antenna and the tuner. I'd bump it up to quad shielded RG11 if you think it would help, but I doubt that (Maybe a dB or 2)?
    I'm just *NOT* going to get 23 am I?
     
  4. BattleZone

    BattleZone Hall Of Fame

    8,969
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    Nov 13, 2007
    It's very possible that a high-quality pre-amp would solve the problem. There are no guarantees, of course, but they often make all the difference. As Scott says, the 2Edge is really the issue. Take a look at the side view profile for that station and you'll have a better idea.
     
  5. kevinturcotte

    kevinturcotte New Member

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    What would be recommended for a preamp? And how would I look at the side view profile?
     
  6. gfrang

    gfrang Hall Of Fame

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    Aug 29, 2007
    Chanelmaster 7777 stay away from Radio shack preamp's,i have a Winegaurd but i think the Chanelmaster is the best.
     
  7. kevinturcotte

    kevinturcotte New Member

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    The bottom of the antenna is at 12' so the top is almost 15'. Would a 10' increase help much/any?
     
  8. Scott in FL

    Scott in FL Godfather

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    Mar 18, 2008
    It's just too difficult to predict. My daughter lives in the mountains of Central PA and has trouble receiving two stations from Altoona: ch 24 and 32. Same distance, same compass bearing. TVFool predicts ch 32 to be 2 dB lower at her house (-68.4 vs -70.5 dBm). So very similar results for both stations. The path is 2edge. Channel 32 just refuses to come in, but ch 24 is OK.

    What I did was take a CM4221 antenna and CM7777 preamp and just walked all around the roof until I found the best location. It's that unpredictable. I found a hot spot that sort of works OK for ch 32, but it's not solid at all. Channel 24 is fine.

    You might want to try that. Try to find the best location. An additional 10' might help, but it's impossible to predict.
     
  9. gfrang

    gfrang Hall Of Fame

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    Channel 10 is vhf high and channel 23 is uhf both are in the same direction and distance,i would look at the antenna and see if the uhf elements are connected.
     
  10. kevinturcotte

    kevinturcotte New Member

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    I'm getting other UHF stations.
     
  11. Scott in FL

    Scott in FL Godfather

    427
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    Mar 18, 2008
    The CM4228HD antenna is a UHF antenna that has about 5 dB of gain on ch 10.
     
  12. gfrang

    gfrang Hall Of Fame

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    Could channel 23 be down?
     
  13. kevinturcotte

    kevinturcotte New Member

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    Not actually interested in ch 10, but would think if I could get that, I could also get 23?
     
  14. gfrang

    gfrang Hall Of Fame

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    One thing is to try a rescan.
     
  15. BattleZone

    BattleZone Hall Of Fame

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    Nov 13, 2007
    Many recommend the ChannelMaster 7777.

    If you click on any individual station in the list grid, you'll see a side profile of the signal path, with any terrain features that are in the way and the predicted signal path:

    [​IMG]
     
  16. Jim5506

    Jim5506 Hall Of Fame

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    Jun 7, 2004
    CM7777 will overload with 6.1 and 8.1 so close.

    Try the Winegard HDP-269 pre-amp.
     
  17. kevinturcotte

    kevinturcotte New Member

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    This is what tvfool gives me for a side view.
     
  18. Jim5506

    Jim5506 Hall Of Fame

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    UHF does not propagate nearly as well as VHF, even with increased power levels, you just can't match VHF for fringe and deep-fringe reception.
     
  19. kevinturcotte

    kevinturcotte New Member

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    I've tried another antenna, the Antenna Direct 91XG http://www.antennasdirect.com/store/91XG_HDTV_Antenna.html. With it, at the same height as the other antenna, I managed to get a 24 on channel 23 without a preamp. This is at 12 feet. I know nothing's absolute, would I potentially get a usable signal if I went up to 22 feet?
     
  20. Jim5506

    Jim5506 Hall Of Fame

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    How much does the potential signal strength change on your TVFool report from 12 to 22 ft? That would be a good estimation.
     

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