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Affect of TV Receive Antenna Height on Signal Strength It Receives

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by W9XMT, Jul 22, 2019.

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  1. W9XMT

    W9XMT Ham Member QRZ Page

    Below is a graphic showing that an approximately linear relationship applies. That is, doubling the receive antenna height above ground ~doubles the r-f voltage existing across the output terminals of the receive antenna (other things equal).

    Elevating the receive antenna sufficiently may provide more improvement than that, if it reduces the propagation losses resulting from obstructed paths such as possible from nearby buildings, hills, etc.


    [​IMG]
     
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    Once you reach line of site, I do not see raising the antenna helping.

    My UHF TV antenna is mounted on the wall inside my house and it works just fine.

    I have one V/U in the attic also. It is higher and works half fast.

    TV is starting to use VHF again.
     
    Last edited: Jul 22, 2019
    K9ASE likes this.
  3. W9XMT

    W9XMT Ham Member QRZ Page

    Actually it will, when the increased height produces higher fields than a line-of-sight path does, due to reinforcing reflections from the ground plane (Earth).
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    OK.

    You have the fancy chart, I don't, So I guess you must be right.

    Have Fun.
     
    AI3V likes this.
  5. WA4ILH

    WA4ILH Subscriber QRZ Page

    Most modern TV sets have a channel signal strength graph built into the menu. I found that useful when I started having trouble with channel 9 (actual channel 9) Yes, I do have some test equipment which I could make a more precise measurment but why?
    Tom WA4ILH
     
  6. W6KCS

    W6KCS Ham Member QRZ Page

    I was having trouble with channel 9 too, coincidentally, even though the strength on the bar graph was pretty good. I hooked up a spectrum analyzer and saw that a lot of other channels were a lot stronger, so I added either 6 or 10 dB (forget which) of attenuation and channel 9 was clear all of a sudden. I ended up rotating the antenna away from the strong signals and things are good. It didn't seem like enough level to overload the front end, but maybe it did.
     
  7. AI3V

    AI3V Ham Member QRZ Page

    If only it were that simple....

    https://duckduckgo.com/?q=fresnel+zone+tv+reception&t=fpas&ia=about&iax=about

    Rege
     
    N0TZU likes this.
  8. AI3V

    AI3V Ham Member QRZ Page

    See above.

    Under certain circumstances it can hurt!

    Rege
     
  9. KJ4VTH

    KJ4VTH Ham Member QRZ Page

    What is this 'TV' thing? :confused:
     
  10. W2WDX

    W2WDX Subscriber QRZ Page

    Are there still many people using the old VHF/UHF analog channels where this has any significance. Digital it either works or it doesn't. Or am I wrong. Most of the stations have to use the repack channels by year end now, right? I haven't bothered checking. I don't watch broadcast TV anymore and do most of my viewing online, since I prefer 4K or higher anyway.

    Been going nutz at the hotel here, on Dish network at 720p and commercials. Ack! And nothing but the same reality TV show on each channel each day. What the hell happened to cable television? One show ... all day?! Really?!

    God I can't wait till I get my streaming services back! To hell with broadcash or cable!
     
    Last edited: Jul 23, 2019

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