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[Towertalk] 80M 4 Sqr resonant point jumps way high...any ideas why?

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Subject: [Towertalk] 80M 4 Sqr resonant point jumps way high...any ideas why?
From: (Nick Wallace)
Date: Tue, 13 Aug 2002 17:42:50 +1200
Hi Paul,

My 4 sqr uses 1/4 wave ground mounted elements and when i erected a 3 wire
electric fence also 4 ft high sometimes closer than a 1/4 wave from the
elements i noticed no change in freq. or for that matter power into the
dummy load.

Nick   ZL1IU
----- Original Message -----

Subject: [Towertalk] 80M 4 Sqr resonant point jumps way high...any ideas

> I use a comtek systems hybred coupler with 4 1/4 wave top loaded verticals
> an 80 meter array.  Testing the system out before the winter season, I've
> found that the array's resonant point has jump 400KHz to apprx 3.990MHz
> where each individual antennas are tuned at +- 15KHz at 3.600MHz.  The
> has always jumped 200KHz, over three rebuilds, using various lengths of
> verticals and top loading wires.  So this major jump on the surface is
> unexplained.  In looking over the array, I have decided to replace the
> feedline connections as some were getting weathered.  I also recently put
> a 4 foot tall 3,800 foot goat wire fence on the west side of the array
> past the 1/4 wave ground radial field.  Could this be the culprit in all
> this.   I am wondering if anyone with a 1/4 wave vertical array has ever
> noticed such a change and if so, what caused it-.  In my research, I have
> found most arrays constructed like mine jump around 100KHz from where the
> individual antennas are tuned due to interaction inside the array,
> and factors in the environment.  The explanation for mine originally going
> 200KHz was that it was in the clear without anything around it- And it
> great!  Now a simple fence is causing it to jump 400KHz???? Can't be that
> simple????
> It's either the 1. Fence  2. Feedlines are screwed up   3. Comtek Box
>  4. One of the verticals is screwed up but this has been ruled out- 5.
> suggestion here??
> The F/B is down a bit, no matter where I am on the band-
> 73  Paul  N0AH/7

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