On 8/8/2013 10:09 AM, donovanf@starpower.net wrote:
I caught a tree on fire at night because the end of my dipole was in some dead
tree branches!
One of the first antennas I hung when I moved here was a horizontal
dipole for 80 with loading coils for 160M, built with THHN. One end was
touching a branch. When I took it down to re-rig it, I discovered that
the white insulation was rather scorched, clearly indicating some arcing
to the branch.
Another thing I tried was loading a 160M wire vertical on 80M, using a
big tapped inductor as a transformer, with a piece of open coax to
resonate it. The coax laid on the ground, which was covered with dry
grass (this was early fall, when we hadn't had rain since April, very
common here). I had only transmitted for a few minutes, and came outside
to see that the open end of the coax, which I had left open because I
was still tuning it's length, had nearly started that grass on fire. The
reason for both of these events is simple -- the points in contact with
vegetation were very high voltage points.
73, Jim K9YC
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Topband Reflector
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