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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