Alan, Steve and All,
Thanks for the feedback.
The antenna is basically an inverted-L antenna. Using approximate
dimensions, the vertical portion is a 110 foot tower, but the attachment
point for the horizontal is down at about 100 feet. The horizontal is
composed of two, 390 foot long wires that form a V with the included angle
of about 50 degrees. The ends of the L wires are supported at about 70 feet
and 63 feet and the wires are single span and have bout 10 or 12 feet of sag
for stress. The antenna is over a set of about 30, #11 radials of various
lengths from 30 to 1200 feet in length. The soil is very dry sand in a flat
in the bottom bowl formed by mountains. The antenna is fed through about
250 feet of 50 Ohm hard line from the shack.
At the base of the antenna, the vertical portion terminates at the input of
a Variometer the other end of which ties to the radial ground system. The
variometer is currently link coupled to the coaxial cable, but the problem
was there when the grounded side of the variometer was tapped up like an
autotransformer, and also when the antenna was fed through a very large
roller inductor / autotransformer. In fact there have been a number of
different feed methods tried and all failed.
If I am not mistaken, the antenna calculated at about 1500 pF.
Nothing I have tried to date has resulted in successful tuning. The most
power I have been able to sustain is about 30 Watts. Higher power has
always resulted in smoke.
The main limiting factor in all this work is the operator... I have
symptoms of early Alzheimer's Disease, and get confused about what I am
doing or where I am in a process. A written step by step which I could
check off as I go would be a great asset.
It is important to the Canadian and possible future US amateur plans for a
LF portion on 137 that I be successful here. We have great resistance from
the power companies with their Power Line Carrier systems here. I am
fortunate that I live in one of the two areas of Canada where 137 kHz is
used for PLC, and the central purpose of my experiments is to get the
station up to full power and show compatibility of PLC and amateur radio.
I have had really wonderful support from Steve and Scott, and have both of
the UK LF books as guides but still cannot seem to get the antenna tuned. I
am familiar with the use of an oscilloscope and maintained the PLC system
which I am demonstrating non-interference with.
As soon as I can get the antenna tuned properly, I can run the power level
up and begin beaconing essentially 24/7 for the remaining months of our
experiments.
Has anyone produced a very detailed first time tuning guide for beginners
like me? I am about 1000 miles away from the closest assistance
(VE7SL/VE7TIL)
Thanks again,
JA
VY1JA
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