[Antennas] Re: Elevated Ground Plane Question
alexander eban
[email protected]
Wed, 9 Oct 2002 10:56:03 +0200
...this is NOT top loading. A few years back MFJ put out what was called at
the time ;Top Fed Antenna. The rationale behind it was that since the energy
goes out at a slent angle from the radials and/or grounplane, feeding the
antenna at the top and moving the ground plane at the top would result in
radiation parallel to the ground. Actually it was shot into the ground! That
antenna was never popular, probably because a lot of guys figured out
something's fishy. The only good thing of that antenna was the size. I
wouldn't recommend it, certainly not as a main antenna!
73 and all the best
Alex 4Z5KS.
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Wednesday, October 09, 2002 5:07 AM
To: W2WU
Cc: [email protected]; [email protected]
Subject: [Antennas] Re: Elevated Ground Plane Question
Top loading is the most efficient form of loading a shortened vertical!
That's true in broadcast or amateur circles :)
But of course the question here does not concern the vertical
radiator but the ground radials...and they should be kept out of the way of
the vertical element....
Chris
WB5ITT
W2WU wrote:
>
> 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.
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