Insulated Support Towers]
Sat, 12 Aug 2000 16:26:28 -0400
Lyle Koehler wrote:
> I've done some very limited computer modeling efforts in which "trees"
> were simulated by grounded vertical wires with resistive loads inserted
> in the middle. If the resistance is very high, corresponding to an
> isolated mast, or very low, which would be the case for a grounded metal
> mast, there isn't much effect even if the "tree" is within 30 feet of
> the antenna. For this crude type of model, losses were most significant
> when the resistor in the middle of the "tree" was a few thousand ohms.
> My first choice from an electrical standpoint would be to insulate the
> mast with a piece of heavy PVC pipe. If that isn't mechanically
> acceptable, then ground it. Probably the present arrangement with the
> board insulator is just fine, unless the board is wet and the path
> between mast and chain link fence is short.
> One of the support towers for my LEK antenna is within 15 feet of the
> flat top. A 3-foot piece of 4" diameter schedule 40 PVC pipe is used as
> a base insulator for the tower, and it's guyed with 3/16" black Dacron
> "antenna rope". Hasn't arced over yet :-)
> Lyle, K0LR
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