Topband: Effect of trees- tree appreciation

[Jim Brown]

On 8/8/2013 10:09 AM, donovanf at 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