Vertical antenna location

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KE0DMC, Oct 21, 2018.

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  1. KE0DMC

    KE0DMC Subscriber QRZ Page

    I plan on setting up s 40 meter antenna. My shack is in an all metal steel barn.
    How far from the barn must the vertical be?
    Thank you kindly.
     
  2. WZ7U

    WZ7U Ham Member QRZ Page

    Are we talking about ground mounting it? Why not mount it directly on top of the barn?
     
    NH7RO, WR2E, KE0EYJ and 1 other person like this.
  3. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    I would also recommend elevating it above the roof level of the barn, if possible. In most cases this will necessitate the use of elevated radials.
     
    NH7RO likes this.
  4. WZ7U

    WZ7U Ham Member QRZ Page

    Which will improve results.
     
    NH7RO likes this.
  5. KE0DMC

    KE0DMC Subscriber QRZ Page

    I'm not keen on climbing up on a fiberglass snow roof. Call it survival instinct. Also its something I have to do myself since I have no one that can help me.
     
  6. KE0DMC

    KE0DMC Subscriber QRZ Page

    Roof is not metal. It is translucent fiberglass snow roof meaning steep angulation. Not sure if a tripod won't be blown off in water storm.
     
    WZ7U likes this.
  7. KE0DMC

    KE0DMC Subscriber QRZ Page

    Elevated radials are out.
     
  8. W9XMT

    W9XMT Ham Member QRZ Page

    What are the L/W/H dimensions of your metal building?
     
  9. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    Okay, you want to use ground mounting. If some circumstance compels you to accept the likely degradation in performance, and you can live with it, that's understandable.

    Unfortunately, I'm not aware of any rule like, "mount it 2 wavelengths away and it will work great. One wavelength is too close." The only rule I know of is a rule of thumb; "the further away from everything a ground-mounted vertical is, the better it works." The point of diminishing returns is, of course, reached when losses in the coax exceed losses from proximity to other structures. It's relatively easy to make an educated guess/measurement to determine the general magnitude of coax losses; losses from proximity are much harder to determine.

    Try to put down at least sixteen radials. The more the merrier. They needn't all be 1/4 wave long; many small radials are generally better than a few long ones. This will help minimize the degradation in performance usually anticipated with ground mounting as opposed to elevated mounting of vertical antennas.

    I don't blame you. When I was in the metal building business a generation ago, the strength of fiberglass panels was nowhere near as uniform as metal ones. We used to say, "Sure, they're all UV resistant sitting indoors at the distributor's. On a roof, some are more UV resistant than others."

    Maybe things have changed since then. But those panels were made in the USA by manufacturers who could be held liable if they failed. Today's panels, fiberglass and metal, are generally made where ever, one run at a time, with Chinese capital (sometimes, but not always, in China itself. But you can't always find out which). No one is accountable to any authority except, ultimately, to the Chinese Communist Party, which generally does not offer much remedy to American consumers...
     
    Last edited: Oct 21, 2018
    WN1MB, KE0EYJ and NH7RO like this.
  10. KE0DMC

    KE0DMC Subscriber QRZ Page

    36 x 48 x 14feet
     

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