Here's a brain teaser that I would appreciate some help thinking about.
The tower in the photo (the big one with the dishes on it) is about 150
ft tall. 32 ft square at the base, roughly 24 ft square at the top.
It's quite well grounded (at least six rods, don't know how long, and
another dozen or so around the perimeter of the building), but I doubt
that there are radials.
http://users.rcn.com/jimbrown.enteract/Photos/Tower.JPG
I want to load the tower on 160. FCC ground conductivity map shows a
boundary along the ridge where this tower is, with 30 to the west and 8
to the east. Elevation at the base is 3,000 ft. There is a rise of
about 80 ft to the west (the direction from which this photo is taken),
then a drop off. The photo is taken from the top of a forest fire
observation tower at the top of that ridge.
Thoughts rolling around in my mind: The tower will obviously tune
pretty broadly based on its cross section, but if you gamma match it,
how do you make the connection to it? Do you run up one side of the
tower to the feed height, tie the corners together at that level, and
feed the center? Do you just feed one corner? Or do you do something
entirely different?
BTW, as a short term solution, I've got a sloping 160/80 trap dipole
running from the top of the tower down to the ground to the east. It
works fine, but there's always room for improvement. :) And we're
planning to hang some more sloping dipoles for other HF bands in other
directions.
Jim Brown K9YC
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