Topband: Beverage array interaction

D Andersen w7dddd at msn.com
Sat May 22 20:24:48 EDT 2004


Hello,

A good test to see the interaction in play is to use EZNEC.  Model a
Beverage antenna and a 1/4 wave parasitic self resonate vertical near it.
Move the vertical all around the Beverage in the model and watch the induced
current in the 1/4 wave vertical.  This shows some very interesting
information!

Don Andersen, w7dd







> Jim is right on the mark.
>
> Because my 160 m antennas are confined in-line on a very narrow ridge
> I have lots of interaction problems between the Beverage and the main
> array.  The Beverage begins about 150' east of the array, directly in
> line with it.  That's much too close for comfort but I have no way to
> change that.  As long as both are looking the same direction the noise
> injection from the main array into the Beverage isn't too bad but when
> the array is firing east and I want to take quick listen to the west
> with Beverage the noise injection is very noticeable because the
> Beverage is looking right into the array.  I have to switch the main
> array to west to cut that down.  I can also get noise when listening
> on the main array from the Beverage.  Of course every time I run a
> test, I get a little different result because the noise is always
> varying.
>
> I think this illustrates the general problem with multiple antennas in
> close proximity, the idle ones can very well inject noise into the
> active one if the idle antennas are not disabled in some manner.   The
> problem decreases with wider spacing but on 160 m that may take a lot
> of real estate.
>
> For anyone serious about improved weak signal reception, this is
> something to think about.  Has anyone on the reflector taken a closer
> look at this problem and have any solutions or observations?
>
> 73, Rudy N6LF
>
>
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