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Do the 150 mile antennas really work?

Discussion in 'Local Reception' started by grunes, Mar 4, 2014.

  1. Mar 4, 2014 #1 of 32
    grunes

    grunes New Member

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    This forum runs a lot of ads for 150 mile TV antennas.

    Various Internet sources claim that most of the time digital TV signals won't carry usably over 75 miles. Presumably that is supposed to be due to limitations of atmospheric transmission, and/or multi-path conflicts, which produce a signal with confused timing. (Satellite dishes are different, because the atmosphere thins at high altitudes.)

    What is actually reliably achievable most places, most of the time?
     
  2. Mar 4, 2014 #2 of 32
    KyL416

    KyL416 Hall Of Fame DBSTalk Club

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    There's too much variables to say it's the antenna alone, what works in one area may not work in another, and in many cases it's the other variables and not the antenna itself that allows reception from that far.


    If you have a clear shot between your location and the tower of a station, no adjacent or co-channel interference affecting the channel, no sources of multipath, potential sources of boost like a large body of water, you can get distant stations on a regular basis regardless of how many miles the antenna is marketed for.
     
  3. Mar 4, 2014 #3 of 32
    BNUMM

    BNUMM Hall Of Fame

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    Just a warning. The ones that advertise 150 miles will pick up at those distances across Lake Michigan. The bad part is that they don't last very long.
     
  4. Mar 4, 2014 #4 of 32
    SolidSignal

    SolidSignal Cool Member

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    I've spent a lot of time researching this. First of all, absent other factors, you will simply not get reception 150 miles away. You just won't. If the attentuation doesn't get you (meaning that the signal is simply too weak for your antenna to pull in, or your tuner to lock onto, the distance is so great that the curvature of the earth becomes an issue.

    In most cases, VHF and UHF signals don't bounce off the upper atmosphere like shortwave signals do. Shortwave signals, and even AM radio signals, can travel incredible distance because they bounce off the upper atmosphere and then off the land, over and over. Usually you don't see that behavior from VHF or UHF.

    In the case of a large calm body of water, two things can come into play. First of all transmitters may be operating at higher power, meaning that the signals go further. Also the extreme stillness of the water and lack of anything in between you and the tower can sometimes mean you get TV signals from further away.

    If you are using a small indoor antenna, it's very rare to get signals from more than 30 miles away, and even with the largest outdoor antenna on a tall mast it's rare to see more than 85 mile range and even that's pushing it. Some areas like Los Angeles have "the perfect storm" where the towers are up on a mountain in the middle of a basin and as you get further away, your elevation increases... and that gives them really good signal where others will not get it. But even there you won't get 150 miles. We have one customer who barely gets 2 channels from 90 miles out and that's pushing it.

    In some cases the use of amplifiers will help you get a little more range or a little more stable signal but an amplifier is not a one-size-fits-all solution. Digital TV signals are much more sensitive to signal-to-noise ratio than they are to pure signal strength so if you have a noisy weak signal, amplifying it to be a noisy strong signal isn't going to do much for you.
     
  5. Mar 4, 2014 #5 of 32
    SayWhat?

    SayWhat? Know Nothing

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    I'm on a hill overlooking much of my surrounding area and I've got a Winegard HD7697P mounted on a 50' tall mast and I can get VHF-HI station about 70-75 miles away. Most of the time the signal strength meter is in the 90s, but it can drop into the 70s or less even in clear weather. I don't lose picture until it gets lower than that though.
     
  6. Mar 4, 2014 #6 of 32
    prozone1

    prozone1 AllStar

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    I'm in nothwest Montana I use a Channel Master 4228HD antenna on my upper deck. Tv Fool says I'm 89.7 miles from tv towers by Missoula. I have no problems getting a strong signal from all 4 broadcast networks.
    Signal passes over Flathead Lake approx 30-35 miles in length
     
  7. Mar 5, 2014 #7 of 32
    kenglish

    kenglish Icon

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    The only place I know of where UHF TV signals carry 150 miles with any reliability is, between two large mountain peaks in Utah. The receive end is a medium sized UHF yagi antenna, mounted at the focal point of a 10-foot microwave dish.

    Those little toy antennas are a gimmick. Use a real antenna instead.
    Most reception is limited to about 30 miles, since that's about the radio line-of-sight between a near-ground receive antenna and a tall transmitting tower.
    You still will often need the gain/directionality of a true antenna, to minimize multipath.
     
  8. Mar 5, 2014 #8 of 32
    CCarncross

    CCarncross Hall Of Fame

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    What Ken said......LOS is only about 3 miles or so at human height....going from a transmission tower to your house, depending on how high your antenna was mounted, 30-50 miles is about it...and there is lots of multipath out there.
     
  9. Mar 5, 2014 #9 of 32
    Gloria_Chavez

    Gloria_Chavez Godfather

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  10. grunes

    grunes New Member

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    I assume you mean that the antennas die quickly. Why? Or do you only mean that the times you can receive that far are few and far between?

    What a great experiment station for studying atmospheric electricity! :sure:

    How often is your antenna hit by lightning? What do you do to protect your equipment?

    If I understand right, my electrician says that the main NEC requirement is that the outer wire of the coax cable, or the mast it is connected to. be grounded by a straight line path. I'm not sure if that would protect solid state electronics, like TVs. He says the NEC development is basically sponsored by the insurance companies, whose main interest is preventing houses from burning down - that protecting solid state electronics is very much a secondary concern. But I'm curious to know what would be needed to do it reasonably well. (Obviously I'm worried about the most likely lightning strikes, not the really big ones with power comparable to a small nuclear weapon, which would be too expensive and too infrequent to worry about. And this page, for ham radio towers, describes techniques that would cost more than the TV.)
     
  11. Jim5506

    Jim5506 Hall Of Fame

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    Most of the Albuquerque New Mexico TV stations broadcast from atop Sandia Peak, elevation 10,664 ft. and theoretically if you are on one of the mountain peaks south of Albuquerque you can get line of sight to these stations.

    I ran a TVFool report from the top of Sunset Peak (33 deg. 35 min. 07.35 sec. N/ 105 deg. 14 min. 06.98sec. W) shows LOS to KASA-TV RF 27 (2.1) effective power 380kw with the NM (db) at 29.6, so if you can find a place where you can get LOSat 150 miles or even 200 miles you should get 24/7 reception with a decent antenna, but such occurrences are very rare.

    For "normal" situations, of course the major factor in reception is terrain (if a hill blocks your reception the signal drops precipitously), second factor is probably local blockages such as trees (especially conifers) and structures. Third is distance where your signal level is inversely proportional to the distance from the source (double the distance=1/4 the signal).

    The biggest impediment to reception a 150 miles is you are so far over the horizon that the tower and your antenna must both be very high with much lower terrain between to get reception as in the case of the Albuquerque area. I am not aware of transmitters anywhere else in the US that are located so high.
     
  12. sregener

    sregener Godfather

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    Antenna ratings in miles are worthless. The only number that matters is net gain. Higher is better for long-distance, but more directional.

    Atmospheric conditions can temporarily produce long-distance reception. Antenna height (both transmitting and receiving) has a huge impact on reliable reception over distance.
     
  13. ziggy29

    ziggy29 Icon

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    There are places in the Sierra Nevada mountain range that get very strong signals (in the green on TVFool) from the San Francisco market, well over 100 miles away. I don't remember the specific locations, as many of them are blocked by mountains from any signal, but I've seen addresses in the High Sierra not too many miles west of the Reno/Tahoe area that listed very strong reception from the SF market.
     
  14. P Smith

    P Smith Mr. FixAnything

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    concluding posts above, we could say - yes, the antenna do really work, but for _very_ rare locations.
     
  15. Jim5506

    Jim5506 Hall Of Fame

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    But, the rest of the story is that those "150 mile" antennas are not as good as antennas made by the major manufacturers, which would give you more signal for the same distance from the transmission towers - cheap Chinese junk.

    All their gain is in the cheap little amplifier, not in the actual signal capturing part of the antenna.
     
  16. Nick

    Nick Retired, part-time PITA DBSTalk Club

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    At 150 miles distance, assuming no significant natural elevation
    or the antenna riding atop a 100' tower to overcome the Earth's
    curvature, any signal pulled in will be crap. Toss an amp into the
    mix and you get amplified crap. Digital, you get nothing, nada, zilch.
     
  17. n3ntj

    n3ntj Hall Of Fame

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    In most cases, you will not reliably receive a TV signal over 150 miles away from its source. The curvature of the earth, antenna height (tx and rx), attenuation, etc. all come into play... but the biggest one will be curvature of the earth at that distance. Commercial TV stations typically have their signal 'fine tuned' to reach approx. 50~80 miles from the tx site (essentially what they call their 'viewing audience').
     
  18. jerry downing

    jerry downing Godfather

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    That would only work if you can see the Chicago skyline from your location across the lake, if not the curvature of the earth would make it impossible.
     
  19. P Smith

    P Smith Mr. FixAnything

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    not that simple, VHF is follow the curvature better, and UHF too in less proximity
    perhaps you are talking about laser or GHz RF connection types
     
  20. AntAltMike

    AntAltMike Hall Of Fame

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    Sorry I'm late coming to the party. If you are concerned with your own reception in College Park, the furthest station you will be able to get with any antenna is in Manassas, probably less than 40 miles away. I service antennas on highrise buildings, and from the rooftop on a 20 story building in Arlington. I can sometimes get the Richmond stations. I once got a channel 4 from New Jersey that is 135 miles away, but even then, that might have been a "tropo ducting" fluke. And since it was just a home shopping channel, I never bothered to try for it again.

    The reception problem you encounter when trying to get distant stations is that their anemic signals are overwhelmed by nearer channels that are either on the same frequency or on the adjacent channel. There is no way to remedy that problem
     

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