[Antennas] Elevated Ground Plane Question

Tue, 8 Oct 2002 09:17:31 -0400

A small "top hat" on a vertical is an old broadcast antenna trick.
I agree that putting radial on top of the antenna would severely limit
current flow and proper radiation.

In fact a large hat would cancel proper radiation. See: Dr. Brown & his
paper on vertical antennas. Also see "Antenna Engineering Handbook" by
Jasik, John Battonson B.E. & other applicable engineering texts.
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Cc: <[email protected]>
Sent: 08 October, 2002 08:29
Subject: Re: [Antennas] Re: Elevated Ground Plane Question

> Put the radials at the TOP of the vertical? Nope..leave them as is....
> They either need to be horiz or slope DOWN...not up...
>
> Chris
> WB5ITT
> Asst Radio Chief Egr
> Liberman Broadcasting, Houston
>
> Ron W7MRR wrote:
> >
> >  Hi All:
> >
> >    I have a 160 meter, 1/4 wavelength wire vertical that is feed
approximately 30 feet off the ground.  The radials are horizonal from the
feed point and parallel to the ground.  I have the opportunity to raise the
radials to a height that is almost as high as the top of the vertical
radiator [approximately 160+ feet] and am wondering if this will enhance the
antenna effectiveness or not.  I am concerned about wave cancelling.
> >
> >    If anyone has a software program where this situation can be
simulated, I would be very interested in the results.  I will try it out in
any case, but am interested in what modeling or experience suggests.  Please
note the radials would now start at the feed point some 30 feet off the
ground with the other end being elevated to 160+ feet.
> >
> - - -
>
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