Warren,
What is the voltage between the tree (GND) and loop? I thought that the
voltages are rather small, i.e. below 100V, especially when a large loop
is used. Isn't it possible to ground the loop?
73, Stefan
Am 26.04.2013 19:21, schrieb Warren Ziegler:
Just a quick report on a failure mode for LF TX antennas.
Last Fall my original TX loop made up of approximately 500 feet of
RG-11 coax suspended from trees went open circuit (both center
conductor and shield), some time later part of the wire actually came
down. I had thought that abrasion from contact with the trees had
eventually worn through it.
What I found was a little more interesting. Looking at the downed end,
it appeared that the insulation had melted for a considerable distance
and there were burn marks further up the cable. My hypothesis is that
the outer insulation was abraded away and the coax shield came into
contact with the tree limb causing the burning/melting.
Will try to get some pictures this weekend and put them up on my website.
Long term if one wants to operate at the kW level either better
insulation or a better way of supporting the antenna than trees would
be required!
--
73 Warren K2ORS
WD2XGJ
WD2XSH/23
WE2XEB/2
WE2XGR/1
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