On Mon, 16 Dec 2013 14:32:41 -0500
"Charlie Cunningham" <[email protected]>
wrote:
Many black plastics are "blackened" by the addition of
"carbon black" that
can make them rather lossy at RF! "Been there, done
that" in my work - at
900 MHz.
I have been using 3" black Derlin (Acetal)insulators at
the base of my 160 m vertical. Because the antenna is only
91 foot tall, there are substantial voltages on the
insulators at legal limit. Indeed, one them caught fire
just after a rain-shower, when water got between the
insulator and the metal. I replaced the burned insulator
with the a new one and covered all the insulators with
high voltage putty. That was about two years ago and I had
zero trouble with any of them since.
George
AA7JV
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