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OTA antenna signal spliter?

Discussion in 'DIRECTV Installation/MDU Discussion' started by hobie346, May 10, 2009.

  1. hobie346

    hobie346 Icon

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    Feb 23, 2007
    Any suggestions for an OTA antenna signal spliter? I did a search on SolidSignal but nothing useful.

    TIA.
     
  2. jdspencer

    jdspencer Hall Of Fame

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    There's nothing special about an OTA splitter. You can probably get one at Radio Shack.
     
  3. Grentz

    Grentz New Member

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  4. robq391

    robq391 Legend

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    Just make sure that if you're going to amplify your OTA signal that you do so as close to the antenna as possible & definately before you split it.
     
  5. hobie346

    hobie346 Icon

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    Feb 23, 2007
    That's what I thought until I bought one from the local RS and then lost channel 12 (DTV 11.1).
     
  6. hobie346

    hobie346 Icon

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    Feb 23, 2007
    Thanks, I don't know why the search I did didn't show anything.

    I bought a MHz to 1GHz one from the local RS but lost channel 12 (DTV 11.1) afterward. The current one shows a -4dB signal lost on both outputs.
     
  7. Grentz

    Grentz New Member

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    If your channel 12 is very weak a splitter could make you lose it. All splitters will have some loss, some are just slightly better than others.
     
  8. jdspencer

    jdspencer Hall Of Fame

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    You probably need to put a preamp on the antenna.
     
  9. carl6

    carl6 Moderator DBSTalk Club

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    Right at 3db per split, or about 1/2 the original signal out of each branch for a 2-way split.
     
  10. texasbrit

    texasbrit DIRECTV A-Team

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    3.5 to 4db is typical for a splitter. Remember if you split a signal two ways you have to lose at least 3db, because 3db means half the signal. You can't have a two-way splitter with a loss of less than 3db, it's just the physics.
     
  11. CCarncross

    CCarncross Hall Of Fame

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    Jackson
  12. hobie346

    hobie346 Icon

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    Feb 23, 2007
    I quess I'll need to add some type of amp to my OTA signal. The question is which the right way to do it? What's better, a pre-amp and seperate splitter or a dist amp? Where does the power get inserted?

    I'm looking at at least one 30' run from the antenna to the spliter and two runs of 20' from the spliter to the receivers.
     
  13. jdspencer

    jdspencer Hall Of Fame

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    I'd put a preamp at the antenna. A distribution amp will amplify whatever noise gets into the coax from the antenna. The power inserter is put before a splitter.
     
  14. Scott in FL

    Scott in FL Godfather

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    Mar 18, 2008
    Noise getting into coax isn't really a problem. The reason you put the amplifier as close as possible to the antenna, and always before a splitter, is because the signal is at its highest level as compared to the noise floor of the amplifier.

    Some think that today's amplifiers are so quiet that this is not a problem, but even an ultra quiet preamp with a noise floor of say 2 dB will contribute a significant amount of noise to a weak signal at the end of a 30' coax run. The result is a degraded signal-to-noise ratio. So always put the amplifier at the antenna.

    Distribution amplifiers typically have higher noise figures than preamps but can handle higher signal levels. A low noise preamp is a better choice at the antenna. But too much gain can cause problems, as can over driving the preamp if you live close to any TV or FM transmitters.

    There's no simple answer. You want a low noise preamp with sufficient gain to overcome any losses after the preamp (from a long coax run or splitters), but without too much gain or sensitivity to overload.
     
  15. hobie346

    hobie346 Icon

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    Feb 23, 2007
    Thanks Scott and JD for the help.

    Any recommendations on a quality preamp?
     
  16. Scott in FL

    Scott in FL Godfather

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    The Channel Master CM7777 is a quality, low noise preamp that many on this forum have had good luck with. It's not cheap, but it's a good preamp. You can amplify UHF and VHF signals separately or combined, and it has an FM trap. I've always used preamps such as this in fringe or near fringe areas with excellent results. If you live close in to any transmitters, be careful. It has a lot of gain.
     
  17. hobie346

    hobie346 Icon

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    Feb 23, 2007
    Does it have any gain control? I live about 46 miles (as the crows fly) from the nearest tower in SF.

    Scott, I looked at the installation of the CM7777 and see that the power inserter is mounted indoors. In my case I have the spliter outdoors. Does the spliter have to be after power inserter or can it be before the power inserter?
     
  18. Scott in FL

    Scott in FL Godfather

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    Mar 18, 2008
    No, it doesn't have gain control, but 46 miles from the transmitters in SF should be far enough away. You might be able to get by with a cheaper solution. But if I were you, and lived 46 miles away from the transmitters, I'd go for the CM7777.

    Aren't there TV stations in San Jose? Be careful... they could overload your preamp.

    There are splitters that pass DC, and splitters that don't. Here is one from Solid Signal that should work well: http://www.solidsignal.com/prod_display.asp?prod=LPD-2

    One side will pass DC, the other side won't.
     
  19. hobie346

    hobie346 Icon

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    Feb 23, 2007
    Thanks for the info.
     
  20. Davenlr

    Davenlr Geek til I die

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    Sep 16, 2006
    Basically...you subtract the amplifiers noise figure and match/balun loss (if used) from your antennas gain to get the system gain of the antenna. Then you match your preamps gain figure to match or be slightly higher than the loss from coax+splitters+gounding blocks. This will prevent overload. If you do end up with an amp with more gain than needed, you can insert a higher loss splitter, attenuator if needed to compensate. The amp will replace the front end agc of the tv tuner.

    I use a cm7777 here in a metro area, with a 15db gain uhf, and 12db gain vhf high yagi feeding it. It works well, unless pointed directly at the local 5 megawatt uhf tower, which will be going away June 12th. I can pick up all locals, as well as several 60-90 mile away stations, depending on atmospherics.
     

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