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OTA Transition - Xmit Power

Discussion in 'Local Reception' started by SE_Sooner, Sep 12, 2008.

  1. SE_Sooner

    SE_Sooner AllStar

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    Aug 12, 2008
    According to www.tvfool.com after the transition on Feb., 2009, most tv stations transmit power will be far less than they currently transmit. Will the coverage map still be the same?

    Most my locals are 80+ miles away but are stable and watchable. Will I have a problem receiving these signals next year?

    Does the digital signal take less power to cover the same area?

    Thanks
     
  2. Stewart Vernon

    Stewart Vernon Roving Reporter Staff Member Super Moderator DBSTalk Club

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    Kittrell, NC
    Some general things...

    All things being equal, VHF tends to travel farther than UHF. This means with equal terrain/weather conditions the same signal strength via VHF will travel farther than UHF... so a VHF conversely doesn't need to be transmitting as strong to go as far. Some stations that will switch down to a VHF frequency in Feb 2009 would not need as much power.

    Analog signals have a range, but there is a point of diminishing quality beyond which the viewer gets increasingly poorer but still watchable TV. Eventually you get nothing.

    Digital signals have a range, but there is a point of increasing signal errors/breakups beyond which you get increasingly more breakups but perhaps still watchable TV. Eventually you get nothing.

    To some, an analog signal with a little snow is preferrable to a digital signal that breaks up, skips, etc.

    In theory, the FCC is attempting to match the digital coverage to the analog coverage today... so I assume (perhaps incorrectly) that someone said channel ZZ is receivable at acceptable quality some distance from the tower in analog... then determined that an appropriately lower digital signal would reach that level and no farther.

    Lots of assumptions on my part, but in theory I think that is what they are trying to do... which means some stations may go lower power if their current power is going past that determined range.

    At least part of that reasoning is to prevent adjacent markets from overlapping and/or interfering with each other. There could also be a side-agenda hoping to see more OTA digital stations popup in the future too, but that's a guess on my part.
     
  3. SE_Sooner

    SE_Sooner AllStar

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    Aug 12, 2008
    Thanks for moving the post to the appropriate forum. My bad...

    HDME, I hope the TV broadcasters and FCC get it right after the transition, for those of us that live on the fringe of the signal, it means the difference in continuing to receive their broadcast signal and nothing at all.

    I guess it's selfish on my part, but I hope they're not to conservative on the transmit power.
     
  4. Nick

    Nick Retired, part-time PITA DBSTalk Club

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    The...
    Don't count on broadcasters to pump up the volume -- the FCC broadcast license limits maximum xmit power.

    For OTA fringe-dwellers, this post may be of interest...or, of concern.
    http://www.dbstalk.com/showpost.php?p=1791416&postcount=153
     
  5. krock918316

    krock918316 Hall Of Fame

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    Where you at SE SOONER? I'm in Poteau. I use a CM4228, and am able to get KHBS-DT, KFSM-DT, KFTA-DT with no problems from Fort Smith. I'm at about 55 miles from KFSM and KFTA.

    Oh and BOOMER SOONER!
     
  6. krock918316

    krock918316 Hall Of Fame

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    Nick -

    Your link doesn't work.
     
  7. n3ntj

    n3ntj Hall Of Fame

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    Yeah, I can 2nd that the link is no good.

    As said, the FCC is trying to get digital radiation patterns to closely match those of the current analog patterns. With many stations changing digital freqs after Feb 2009, I think some modifications may be made, but probably on a station-by-station basis.

    The stations moving from their current UHF digital freq to their current analog VHF freq (for digital), they may very well be able to lower their ERP to get comparable radiation patterns.

    One thing I can say about Feb 2009, it should be an interesting time for TV... especially those into DX TV..

    See the Digital/Analog TV Plug-in available for Google Earth. Way Way Cool!
     
  8. SE_Sooner

    SE_Sooner AllStar

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    Aug 12, 2008
    I'm about 40 miles west of you in Wilburton. I can get 40/29 but none of the other Fort Smith stations. I do however get channels 2, 6, 11 and 41 out of Tulsa. Also, PBS out of Eufaula and channel 10 from Sherman/Denison TX. Some of the other Tulsa stations are come and go.

    I was reading on other posts that some have good luck with a Channel Master Amp. Will this help on the marginal stations? OBTW, I'm using a old UHF Yagi antenna about 6 feet above the roofline.

    We'll see what the Sooners can do with Washington this evening!
     
  9. Richard King

    Richard King Hall Of Fame

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    Fixed link. Try again.
     
  10. krock918316

    krock918316 Hall Of Fame

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    Wife used to work in Wilburton. Thank goodness she got to transfer back to Poteau. That was a lot of gas money with her driving from Poteau to Wilburton every day, and me driving from Poteau to Fort Smith every day.

    80 miles is definitely fringe. There are so many mountains in between you and KFSM and KFTA that I think it will be tough, especially since both are currently on UHF (and UHF doesn't travel as well as VHF).

    With me at 55 miles, and my antenna pointed at KFSM and KFTA, I am only getting about 55-60 on my HR20's signal meters. I am using the CM4228 antenna and a Channel Master 7777 pre-amp.

    I wish I could get KTUL. 40/29 drives me crazy preempting ABC games (usually the Sooners) for a Raycom game.

    Now that 40/29 is broadcasting The CW on 40-2, they are using their HD tape delay unit to do commercials on CW, so all preemptions are are in SD (and their SD tape delay unit looks like it is a 20 year old VCR).
     
  11. SE_Sooner

    SE_Sooner AllStar

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    I read somewhere, maybe on KTUL website that their xmit antenna is shaped to not cover anything south of I-40. I can't get it but I don't have a VHF antenna and I think there're still in the high VHF range.

    So does your 7777 pre-amp help with drop outs? When my signal get below 60 things get iffy.

    Hey, isn't 40/29 transmitting from Cavanal Hill? The TALLEST HILL IN THE WORLD!
     
  12. krock918316

    krock918316 Hall Of Fame

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    Yes, KTUL limits their signal south of I40 to stop interference with another station. I believe that KTUL will be moving their DT transmission back to 8 when the DTV transition happens, so that might eliminate the problem south of I40.

    The CM7777 just helps with the signal overall. Without the preamp, my KFSM and KFTA signal drops to about 40, and is very pixelated.

    Because I'm so close to Cavanal, I actually have a lot of problems with 40/29 because of multipath. I really need a second antenna with a filter, so that I can point that antenna at Cavanal, just for 40.

    You might try coming over to the AVS Fourm for Fort Smith OTA. We have a real antenna expert "ARXAW" and the engineers from 4029 post a lot, and can offer a lot more help. Here's the link: http://www.avsforum.com/avs-vb/showthread.php?t=463765

    BOOMER SOONER!
     
  13. SE_Sooner

    SE_Sooner AllStar

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    Thanks for the invite... I've got some questions about combining antennas in different directions, and the best way to do that. Because splitter/combiners suck.

    7 to ZIP
     
  14. krock918316

    krock918316 Hall Of Fame

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  15. SE_Sooner

    SE_Sooner AllStar

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    The Jointenna sounds like the gear I need. I didn't see any specs on their website, like db loss etc. I think I would be ok with a CM 7777 pre-amp and the Jointenna. Logically, any loss caused by the Jointenna would be offset by the pre-amp. But I could be wrong. The only reason I worry about loss is the fact that I'm already marginal on sig. strength.

    Thanks for the link.

    20 zip
     
  16. krock918316

    krock918316 Hall Of Fame

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    No problem!

    27 zip
     
  17. n3ntj

    n3ntj Hall Of Fame

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    This isn't viable if you are trying to receive multiple channels from 2 or more antennas!
     
  18. krock918316

    krock918316 Hall Of Fame

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    Actually, you can.....

    [​IMG]
     
  19. krock918316

    krock918316 Hall Of Fame

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  20. n3ntj

    n3ntj Hall Of Fame

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    Since you'd have to purchase one of these for each channel you want on the 2nd antenna, I don't see that as a 'realistic' option.. maybe 1 or 2 stations, but not all the stations from another city. For example, I use one of my antennas for my local stations (Harrisburg/Lancaster, PA) with a pre-amp and then another antenna for the Phily stations (5 or 6 stations in all).
     

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