I had an 80 meter two element parasitic vertical beam array with elevated
radials. The radials were roughly 8 to 10 feet in the air and 8 radials per
vertical. They were suspended through the woods by tree branches and installed
so there was roughly a foot of vertical clearance between the radials on the
driven and the reflector (reversible) where they crossed.
(In those days I was drinking the Kool AId and believed in quarter wave radials
with religious fervor)
The vertical elements were full size and supported by the phillystran guys on a
150 foot tower. It was fed by a Henry Classic amp with a pair of 3-500 tubes
and were were running about 1400 watts.It would hit 1800, but with long runs of
CQ it would start to smell hot, so we sacrificed a tenth of a dB (the horror,
the horror) and backed off 400 watts
It was CQWW CW and a cold, wild, black, night with a howling wind. Dave went
out for a smoke and came running back in."There is fire raining from the sky"
he yelled. "It went down the back of my neck and burned me.""Aww, come on
Dave" I said smugly, not even turning around as I bagged a multiplier on 80.
"No sheet" he yelled, his eyes still bugging out.
Long story short: WIth the big halogen light we determined it was the radials
waving up and down and touching when the wind whipped the tree branches. Next
day we got a ladder and looked at the radials, #14 THHN, and the insulation was
charred off where they touched and the copper was pitted and melted in spots -
with one in particular, almost cut in half..
So the voltages 2/3 of the way out on a radial, at 1400 watts, are an eye
opener.Anyway, the antenna was a pile up buster and worth its weight in gold
during a contest - but the constant, never ending, chore of broken tangled
wires and tree limbs year around was its undoing in the end.
denny / k8do
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