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[Towertalk] Fence fence go away-

To: <towertalk@contesting.com>
Subject: [Towertalk] Fence fence go away-
From: n4kg@juno.com (n4kg@juno.com)
Date: Fri, 16 Aug 2002 08:10:47 -0600
N4KG comments inserted below.

On Tue, 13 Aug 2002 Dinsterdog@aol.com writes:
> Ok,
> 
> As a follow up on my 4 SR problems since installing a 3000 foot 4 
> foot high goat wire fence within 60 feet on the west side of it, I 
> have a question on making the fence disappear.  Moving it will be 
> tough, but if I ground it, will it go away as far as the array is 
> concerned?  

The short answer is NO !

Think of a Yagi with insulated elements.  ANY conductor longer
than 1/2 WL out to several WL  WILL act as a reflector.  ANY
conductor between 0.3 and 0.5 WL WILL act as a director. 
The ONLY way to make a conductor 'invisible' to another antenna 
is to make it appear as something LESS THAN 0.3 WL at the
operating frequency.  

I see a few possibilities:

Break up the fence wires with insulators (Bye Bye electric fence)

Use Non-conductive material for the fence near the array.

MOVE the Fence.

MOVE the ARRAY.

GOOD LUCK !

Tom  N4KG

To RF ground it as far as the array is concerned,  I was 
> thinking of attaching 66 foot redials to the bottom of the fence, 
> which is made up of 12 gauge woven wire, and running them out away 
> from the array.  Has anyone ever attempted to RF ground a fence of 
> this length?  Does the radial idea make sense?  The array is acting 
> wacko and everything else that could cause problems has been 
> eliminated.  Symptoms of the arrays problems include a raised 
> resonant point from it's standard 200KHz to 400KHz, varying power 
> port dump readings from 1% to up to 20% at resonance, and the 
> individual resonant points of the two closest verticals, which 
> parallel the array on the west side, dropping from 3.620MHz to 3.577 
> and !
> 3.543 respectively.  The two furthest verticals have not been 
> directly effected as far as resonant and SWR readings. The vertical 
> closest to the fence (66 feet) has the lower SWR and the other 
> vertical which parallels the fence on the west side (75 feet from 
> fence) is the other that dropped.   And oh yeah, the F/B sucks- 
> Rather than moving 600 feet of fence, can anyone suggest a creative 
> solution?  Much appreciated-
> 
> 73  Paul  N0AH

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