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Max TV antenna coax length?

Discussion in 'Radio and Communications' started by AGCB, Nov 22, 2014.

  1. AGCB

    AGCB Member

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    My brother lives in a low area about 80' lower than I and gets poor TV reception. There is a 100' hill near him which would result in a cable length of 300 - 400'. Is this possible w/ any kind of coax or is there another way of getting reception from that hill? We live 300' apart and I get reasonably good reception.
    Thanks
    Aaron
     
  2. MikeMl

    MikeMl Well-Known Member Most Helpful Member

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    Since the stations move to UHF (digital), you will need a preamp right at the antenna to go much over a hundred ft.
     
  3. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    How far do cable TV wire run?
    There is loss in the cable. How much depends on the type of coax.
    I would add a "antenna amplifier" close to the antenna. Maybe not on the antenna but somewhere handy and close. I have one amp that has only one input and one output. I also have one with 1 in and 4 out. (amp + splitter) By the time you split the signal 4 ways you loose most of the amplifier's gain.

    At your house I would add the amplifier with a built in splitter. One output goes to your house and another output goes to the brother. If your brother is getting a weaker signal then you, add a simple amplifier in his line. (At your end of the wire)

    Because every splitter losses signal; Boost up the signal, split (you/brother) then boost ahead of the 300 feet of wire to make up for the long wire.
     
  4. dave

    Dave New Member

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  5. AGCB

    AGCB Member

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    Just to clear up my post. This will be only for my brother. My TV is good as is.

    I was planning to use an antenna mounted preamp. So, that being said, is 400' too long a run for coax?

    On another post someone mentioned RG-11 as being better in some ways than RG-6. This cable would have to run on or under ground. If under, then probably in conduit. My brother works for a company that installs underground conduit who told him they would do it for the price of materials.

    Is it possible that there is another way (if 400' is too long) to get the signal to the house?

    Thanks
     
  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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  7. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    www.tvfool.com has the ability to estimate the signal at a particular location. You can use lat and long and antenna height. I have no idea what the agreement is takig into account of the antenna gain, attenuation and amplification for where I live. I do have the capability to measure the 8VSB signal strength.
     
  8. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    The coax is easy, use low loss cable.
    The hard part is you will need power up there too.
     
  9. MikeMl

    MikeMl Well-Known Member Most Helpful Member

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    Most preamps are powered by DC between the center conductor and the shield. You insert the DC using a wall-wart and a "Bias Tee"
     
  10. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    Yes and that was my point, Coax is easy, If you wanted to use, say a transmitter you would have to run a wire up there anyway for power.
     
    Last edited: Nov 22, 2014
  11. AGCB

    AGCB Member

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    Thanks for the replies. I'll look into this more.

    Aaron
     
  12. MikeMl

    MikeMl Well-Known Member Most Helpful Member

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    Arron,

    A typical UHF preamp has a gain of only 18db.

    400ft of RG6 has a loss of ~30db at 800MHz, so I think you need better coax, or a better preamp.
     
  13. 4pyros

    4pyros Well-Known Member Most Helpful Member

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  14. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    That was my guess. It would take two pre-amps to overcome the loss in 400 feet.

    The real loss is from sitting behind a hill.
     
  15. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    If your considering a rotor, then there are wire type and gauge issues to consider as well. Most TV rotors are designed for <100 feet of cable. If you do decide to run rotor cable, consider the choice CAREFULLY! and plan for it to be replaced by something else.

    I have a distribution amp made by these guys: http://www.tinlee.com/HeadendDiagram.php?active=4 I linked to a "what you need to know" page.

    I'm distributing a signal to up to 12 locations with a rotor and a mast mounted pre-amp. I think I am amplifying at the antenna; in the attic and for final distribution using taps. The antenna is the Winegard HD8200U, which is huge. I'm also using a bearing and non-conductive guy wires.

    Bear in mind, you can also amplify in the middle as well, if the signal is good.
     
  16. nsaspook

    nsaspook Well-Known Member

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  17. Scotophor

    Scotophor Member

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    If you're going to mount an aerial on a hill, do NOT neglect to install some serious lightning protection!
     
  18. AGCB

    AGCB Member

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    Deciphering all the great info!

    Thanks
    Aaron
     
  19. 4pyros

    4pyros Well-Known Member Most Helpful Member

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  20. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You don't want a 'preamp' - you want a 'launch amp' - these have much higher gain, and power output.

    However, they aren't normally line powered, so require a mains feed.

    Another option, is multiple line-powered preamps, at various distances down the cable run - you can add an RF choke to bypass power past the intermediate amplifiers.

    We did this decades ago for a place called 'Lathkill Lodge' - the aerial was on a pole partway up the hillside (where there was a line-of-site to a very distant transmitter).

    There was a preamp on the aerial, a preamp partly down the hill, another preamp at the top of the cliff, with the cable going down the cliff and across the river to the house :D

    During a later repair job we had to replace the cable across the river, so cut the existing cable at the bottom of the cliff, and added a fourth preamp :D

    Like I said this was decades ago, and the amplifiers were fairly crappy Labgear/Philips ones, more modern amps give much better performance.

    This was the location:

    https://maps.google.co.uk/maps?ll=5...noid=3FF9PQouY6I2XOWnJR0_3Q&cbp=12,84.39,,0,0

    Looking on StreetView the house is the white walled building, and the aerial was across the river, where the footbridge goes - next to the ford - where we used to drive across and up a track to just above where the aerial was sited.
     
  21. 4pyros

    4pyros Well-Known Member Most Helpful Member

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    Nice stretch.
    Would not a single high power amp give you a better signal, less noise?
     

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