[BC] unusual antenna components
DANA PUOPOLO
dpuopolo
Tue Feb 28 12:17:53 CST 2006
There was a CP UHF TV antenna manufactured that was a helix of stainless steel
wire. One of its sale points was that it did not need de-icers!
I wonder where the heating voltage came from??
-D
From: "Craig Healy" <craig at craighealy.com>
> Craig Healy had suggested to me that the problem might well have been
> use of aluminum wire for the folded unipole. The higher resistance
> wire slows the propagation velocity in the folded unipole..
Actually, I thought I said stainless steel wire. The resistance of that
can cause a drop in efficiency simply due to the IR losses. Aluminum
would probably work, if the electrolysis can be controlled. The velocity
of propagation wouldn't be affected by the wire type.
I have a sometime radio station client that had a consultant come in
and use 1/8" stainless aircraft control cable. The resistance of that
measured out to be close to .7 ohm per ten feet. The consultant further
screwed up by going beyond the most efficient point of connection. He
went to the top of the tower, and the resultant base resistance was a
lousy 10 ohms. Mucho loss there..
Further evidence of efficiency loss was in the final tower ratio. It
dropped from a previous value of maybe 70% to 29%. All due to the
reduced efficiency of that tower in the array.
The owner was notified, but he doesn't seem to care. (shrug) I did my
duty by informing him.
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