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[Towertalk] C31XR & guy wire detuning

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Subject: [Towertalk] C31XR & guy wire detuning
From: (Pete Smith)
Date: Thu, 25 Jul 2002 08:54:46 -0400
At 08:12 AM 7/25/02 -0400, wrote:
>In a message dated 7/23/02 12:50:44 PM Pacific Daylight Time,
> writes:
> > I want to break the 54' sections into two segments each. My question:
> >
> >  What should the lengths of these two sections be to minimize their
> >  interaction with the C31XR?
>     There are 2 things at work - the antenna and the guy wires. First, you
>need to see if  it's a guy problem by keying the radio into the antenna and
>then turn it while you watch the swr. If the swr varies as it turns, then
>it's guy wire interaction. If it doesn't change, you've got an antenna

Steve, I think that's too simple.  If the SWR doesn't change when it turns, 
it MAY not be a guy wire problem, but you can't be sure because not all 
destructive interaction affects SWR,and the placement of the guy wires may 
be such that their effect is more or less independent of antenna rotation.

As an example, my F12 EF-240S is at 104 feet, above a C-3E and 9 feet above 
the tops of the uppermost guy wires, which were grounded at the bottom but 
insulated from the tower.  Rotating it showed no SWR variation, but the 
antenna was an indifferent performer.  Then, in order to accommodate a 
tribander stack, I replaced the top guys with Phillystran, and the antenna 
clearly and strikingly "woke up."  Since the guy wire change was the only 
change in the near field or in the antenna itself, I think the inference is 

73, Pete N4ZR

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