When thinking about antenna design one should look at the people who have a
working, COMMERCIAL, money making system that works. Go look at a AM broadcast
tower in your area. Ask for a tour from an ENGINEER there.
Almost guarantee you will find a tower that is pin mounted. Why, you ask?
That is the way towers are made to be installed. (IMHO of course) This is the
only way a tower can twist and flex, and believe it or not a tower must move to
be strong. Climb a tower past the 500 foot mark and feel how much it moves in
a bit of wind.
Granted, its EASIER to stob a section in the ground and climb, stand and hang
your antenna creations on. Yet know this, anything in the wind oscillates.
From bridges to skyscrapers. It is measurable less stress on the tower when it
can twist and move in the wind.
For ya'll that need some fancy words, try these: dynamic torque loading of the
antenna, K-factor computations for overpowering horizontal load vector limits.
Also read Electronics Industry Association Structural Standards for Steel
Antenna Tower and Antenna Supporting Structures - EIA/TIA-222-E.
ALL I'M SAYING IS don't disregard pin mounted tower because you don't or wont
understand them. Once you have it installed, it really is the best way. Never
have to worry about the legs filling with water and bursting again to boot.
de KE4VYN
Lee
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