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Re: Topband: Chain link fence signal coupling

To: "Bruce" <K1FZ@verizon.net>, "Topband" <topband@contesting.com>
Subject: Re: Topband: Chain link fence signal coupling
From: "Herbert Schoenbohm" <herbs@vitelcom.net>
Date: Wed, 21 Nov 2007 09:37:04 -0400
List-post: <mailto:topband@contesting.com>
 Bruce K1FZ asked:

> Anyone had first hand experience with a Beverage antenna too close to a
> chain link fence? How much separation was necessary to get reasonable
> Beverage antenna directivity? Was grounding of the fence tried, and did it
> help?

> #1 with the Beverage pointed at the fence

> #2 with the Beverage running parallel to the fence

Bruce, A 6 foot chain link fence surrounds my property.  Some of my
Beverages in a former hay field south of my property run for a 150' or more
parallel to that fence with a separation of about 30 feet.  Chain link fence
is somewhat grounded by the many steel support posts.  Some of the
bi-directional Beverages actually cross over the fence at right angles so I
can better maintain the feed lines inside the yard..  (The other feed lines
running out in the field disappear in the grass and cactus within months.)
Being concerned about the proximity of the fence I ran 1000 feet of RG-6 out
to a comparison 600 footer so I could run A/B tests.  If there is any
deterioration in performance on forward signal level is so small that is not
noticeable here.

There may be other issues such as coupling to other noise sources, reduced
directivity, and F/B, and IM coupling. But not here. But as said so many
times before, a Beverage is a very forgiving RX antenna such as crossing
over other Beverages, fences, uneven terrain, zig zag lay out, and even poor
grounding at either end......the still seem  here to always work better than
anything else such as verticals and inverted V's.

Such Beverage constructions near fences may not be text book perfect but
even so it may be the only option and should still be worth the effort.

Herb Schoenbohm, KV4FZ

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