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Re: Topband: Cage wire performance

To: "Richard (Rick) Karlquist" <richard@karlquist.com>, Kenny Silverman <kenny.k2kw@gmail.com>, TopBand List <topband@contesting.com>
Subject: Re: Topband: Cage wire performance
From: Joe <nss@mwt.net>
Date: Mon, 4 Jan 2021 11:10:18 -0600
List-post: <mailto:topband@contesting.com>
So this is more or less like the Bow Tie Dipole antenna that is used like in UHF TV antennas.

Sometimes two wires on each side like cat whiskers.
and other times a solid triangle on each side.

Now I wonder, is there a limit say ratio wise to length vs width at the far end, where you don't get any more bandwidth, or it no longer even acts like a dipole?

Joe WB9SBD

On 1/4/2021 9:32 AM, Richard (Rick) Karlquist wrote:

On 1/4/2021 7:05 AM, Kenny Silverman wrote:
where the wires connect at a point on the top, but with a 4 foot spread of the wires near the ground. This adds about 15-20 kc to the 2:1 bandwidth per the model.

Will a 2-wire section like this always behave as a wide/fat conductor or do I have to worry about voltage/current in Each wire?

Regards , Kenny K2KW

Just a guess:  I would think with 2 wires, you would be fairly
successful with getting good current sharing, as long as there
wasn't some unbalancing effect, say due to having the vertical
running along side a tower.

With 3 wires, there is some reason to think that the middle
wire wouldn't carry much current if the three wires were
in a plane.  OTOH, if they formed a triangular cross section,
then it would seem likely that current sharing would be good.
In general, you want to emulate a round conductor, as opposed
to a strap.  When straps are used to make inductors, the
current crowds to the edges.  Round conductors don't have
such edges, hence they have good current sharing.

I don't believe NEC is good for modeling this.  You have
to use a tool called "HOBBIES" if you want to do this.
K6OIK has written some articles about this tool.

73
Rick N6RK
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