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[Towertalk] Interaction of Verticals

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Subject: [Towertalk] Interaction of Verticals
From: (
Date: Tue, 6 Aug 2002 19:53:41 -0600
Interaction between the verticals is not the only problem.

A grounded tower with Yagi's on top WILL act as a 
non-resonant reflector for 40 and 80M verticals.  
I've seen this problem with 50 and 70 ft spacing on 80M.

The 40M vertical will be invisible to the 80M vertical.
The 80M vertical may or may not interact with the 40M
vertical, depending on the impedance (at 7 MHz) between 
the base of the vertical and ground / radials.

I still think the MFJ 1792 is an interesting alternative vertical
for 80 / 40M (with admittedly narrow bandwidth on 80M) at a 
an attractive price.

Tom  N4KG

p.s.  Please include your callsign with your signature.

On Tue, 06 Aug 2002 writes:
> Hello All
> I am looking at putting up two verticals as spare antennas
> on the 40m and 80m. These are meant to be something for 
> use in SO2R, a multiplier radio, or just another choice 
> in a growing antenna menu.
> What's the feeling on how close I can mount two separate 
> verticals without interaction? These would probably be 
> full size 1/4 wave antenna's and I hope to be able to 
> put 18-24 inches between them. Only one would be used at a 
> time.
> If there is a problem with interaction, what if detune 
> the vertical not being used? 
> 73
> dink
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