S3, Antennas & Lightning concerns

Discussion in 'TiVo Series3 HDTV DVRs' started by astrohip, Sep 4, 2007.

  1. Sep 4, 2007 #1 of 10
    astrohip

    astrohip Well-Known Raconteur TCF Club

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    Houston/Bren...
    [I realize this may not be the exact proper forum for this question...]

    I have an S3 that is driven by two cablecards. I also have a pixellation problem that started this summer, and I have not been able to resolve it. There are 4-5 channels that have problems, but the two that concern me the most are the HD feeds for NBC & ABC (312 & 313 ComCast Houston). With the new TV season almost upon us, I have to do something. I've tried high quality amps & splitters yada yada; I won't bore you with pixellation talk--there's a dozen other threads for that. :D

    My solution is to put up an antenna, and use that to record the HD OTA channels. This being Houston (avg elev: 12 ft; avg elev variance: 3"), antennas work well. I'm gonna clamp an antenna to the edge of the roof, run a coax to the S3, and watch my boob tube.

    Do I need to be concerned about lightning? We get a LOT of it here. The antenna will not be the high point on the house; it will be 12-14 off the ground, the house is 25' at its peak. And we are surrounded by a fair number of tall trees. Plus there is a utility pole with all sorts of wires on it about 15-20 feet away, around 15-20' high. Will an antenna "attract" lightning more than other objects? And is there any protection (for the S3) I should take...just in case?
     
  2. Sep 4, 2007 #2 of 10
    classicsat

    classicsat Astute User

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    There should be a diagram at the beginning of the manual about kooking up and antenna and properly grounding it and the mast.
     
  3. Sep 4, 2007 #3 of 10
    Dr_Diablo

    Dr_Diablo Dr_Diablo

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    I think that using at least a 16 guage wire grounded to the atenna, then to a rod buried into the ground at least 3 to 4 feet, should do the trick...

    If you haven't then think battery backup an a good quality surge protector for the electronics...
     
  4. Sep 4, 2007 #4 of 10
    morac

    morac Cat God TCF Club

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    Being high up and made of metal, it is possible that the antenna could attract lightning, but considering lightning jumps across a few miles of air (which is a good conductor), the metal probably won't really make much of a difference. Lightning tends to strike taller objects, but that's not a guarantee.

    The main difference is that if lightning does strike anywhere near the antenna, the antenna wire will feed the electricity directly into your S3 which would instantly kill it (and probably all other equipment in your house). More than likely though if lightning struck that close to your house it would cause a surge in your home electrical wires frying all electrical equipment plugged into the electrical outlets in your house any way.

    You can protect against non-direct lightning strikes by connecting the antenna to the house ground and using a surge protector with coax support, but nothing will protect against a direct lightning strike except a good home owner's insurance policy.

    Recommended reading (check pages 44 to 47).


    Another choice is you could use an indoor or attic antenna.
     
  5. Sep 4, 2007 #5 of 10
    Laserfan

    Laserfan Member

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    I agree w/morac, and support also his conclusion. Unless you are 30 miles or more from the transmitters, a good indoor antenna should be all you need. Then at least you don't have to worry about lightning frying your S3 at the Ant Input (you do of course have surge protection & ups on your S3's power cord already, yes?).

    I am a few hours west of you in the Hill Country where we have lots of lightning also. I use a Philips "silver sensor" indoor antenna despite that I'm 35 miles west of Austin. Works great.
     
  6. Sep 5, 2007 #6 of 10
    vsbdtv

    vsbdtv Custom User

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    There are often local code requirements for grounding, although many such requirements reference some version of the "National Electrical Code". Even then, the requirements can vary depending on the grounding of existing structures, length of grounding conductors, etc. In general though, it's usually inadequate to ground an outdoor antenna to a grounding rod only. A common ground is needed to eliminate potential grounding loops.
     
  7. Sep 5, 2007 #7 of 10
    astrohip

    astrohip Well-Known Raconteur TCF Club

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    Houston/Bren...
    Thanks for the feedback everyone. Based on what I'm reading here, I think I will start out with the antenna inside, rather than outside. If it's good enough, I'll save myself a bunch of trouble.

    And yes, I have *all* of my TV/computer related equipment on UPSs. The cable modem, router, server, TiVo, etc.
     
  8. Sep 5, 2007 #8 of 10
    CCourtney

    CCourtney Member

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    El Dorado...
    There's always a chance of lightening striking. Proper grounding can still result in damaged equipment if struck by lightening w/o surge protection on the antenna cable itself. The proper grounding is more to make sure your house doesn't go up like a BP petrolchemical plant.

    I'd recommend an attic antenna instead - < $50 at Home Depot or Lowes. Or you can go an even cheaper route w/ a TV top antenna. I'm using the Terk DBHDTVI passive antenna on top of my TV currently w/ excellent reception, and I used an attic antenna at my old house (moved in May.)

    CCourtney
     
  9. Sep 5, 2007 #9 of 10
    afiggatt

    afiggatt New Member

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    Putting the antenna in the attic is easier and means you do not have to deal with wind & weather. I get stations from 43 miles and further away with an Channel Master 4221 4 bay bowtie in my attic. But you should check the construction material - slate roof, radiant barriers can be a problem.

    antennaweb[dot]org is a good starting point for antenna info, where your local digital stations are and their current channels. Antennaweb is very conservative on digital reception, so even if you enter your exact address, add 75' or more for antenna height under the options link to get a more complete list of your digital stations. Another site for stations and predicted signal strength is tvfool[dot]com.

    A quick check shows that Houston currently has one digital station on upper VHF 9 (KUHT-DT 8), the rest are currently on UHF. But two stations, KHOU-DT 11 and KTRK-DT 13 will be switching from UHF to their analog upper VHF channels after the analog shutdown in February, 2009. So you need an antenna which works for UHF and upper VHF. If you need more specific antenna advice, post your zip code. I have been doing this enough on avsforum...
     
  10. dagap

    dagap New Member

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    Alpharetta, GA
    +1 for attic-mounted antenna. I hung mine upside-down, with the pole mounted to a rafter.
     

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