TopBand: 160m Ground Systems

[DAVE - N7EX]

At 02:31 PM 2/10/97 -0500, Bill Cotter wrote:
>
>What I haven't been able to resolve from Lee's books or Brown's and
>Jasick's texts, are the consequences (or lack of benefit) of not observing
>the statement below concerning the bonding of radials in a field. What if I
>don't bond together the radials as they cross? I suspect most amateur
>arrays are this way.
>
>I have installed a 40m 4-sqr array with 64-radials per radiator. About half
>of the radials are #14 enameled wire and the other half are #16 plastic
>covered wire. None are bonded together as they cross. The only bonding
>between the radiator ground systems are the outer braid of the feedlines to
>the ComTek box. Will I expect less than perfect gain, directivity, F/B
>Ratio, or Radiation Resistance? Should I expect something more insidious
>like arcing, static or who knows what. Or, as I suspect, no discernable
>consequence.....  Comments/experiences please.

Bill

One possible consequence based on a personal experience is that if the two
radials are "touching" (insulation to insulation) each other that with time
(insulation breakdown)and high power, that arcing can actually occur
causing SWR problems and TVI or as in my case even a fire! 

In my case I has a raised radial system that was tacked in a couple of
places to a wooden privacy fence. In some cases the radials while insulated
touched each other. I was experiencing SWR problems but only at high power
(at 100W everything was OK). Thinking that the problem was with one of the
two antennas (phased Butternut verticals) I had the XYL periodically key
the rig while I went out on a darkened night expecting to find something
arcing on one of the verticals. I had been testing on and off for 15
minutes when as I walked out the back door the wooden fence burst into
flames at the crossover of two of the radials!! The fire was quickly
exstinguished and I counted my self very lucky..lesson learned ~8^).

Theoretically with more radials the current in any given radial should
theoretically be less so possibly the fields involved in a system with a
large number of radials might not be as large and the "potential" for the
above problem might be lessened. In the example above there were only 4
radials per vertical (8 total). Just one bizzare personal experience.

Dave
N7EX


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