I have seen some rather nasty outcomes when steel guy-wires are replaced
with plastic. The makers of Phylistran will tell you that you still need
the usual porcelain insulators installed in their synthetic guy-wires in
many applications. I have seen the stuff melt in a matter of seconds at
power levels as low as 10 kw where a steel guy-wire was tuned as a
reflector, and the top portion of this guy was 30 feet of Phylistran. So
the possiblity exists that a ham radio QRO sloper or hot-guy-wire
installation might suffer a similar fate if the RF voltage gradient across
the Phylistran is high enough. Corona rings offer limited improvement to
voltage gradient unless very carefully designed, and they also increase
windage, of course. At any rate, take care when using plastic in high RF
fields when your tower's structural integrity is at stake. Be sure to
contact the manufacturer of your rope and get his expert opinion about your
application.
Grant Bingeman
KM5KG
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