I am starting to put up a real tower and antennas and a few questions
have come to mind which undoubtedly have answers somewhere among the
multitude of Reflector users.
For various reasons, I will probably be putting up a 72' crankup
(US Tower or equiv) with a 3 ele 40 (probably) on the bottom and a
tribander (such as a KT34XA) up 10 feet or so. The tower is rated
at 30 square feet in a 50 mph wind. I'm sure that is 30 SF at the
top of the tower (or, maybe, 2 feet up). Obviously, a KT34XA (9 SF)
which is mounted 10 feet above the top of the tower has a windload
in excess of 9 SF on the tower.
My questions are as follows:
- What is the windload of a 3 ele 40 by KLM? What is the
windload of their 2 ele version? I can't find anything
on this.
- Is there a handy formula to determine the windload at the
top of the tower for an antenna mounted X feet up?
- Should I enlarge the concrete base if I do this? I guess
I'm really asking whether the weak point in such a setup
is the base or some other tower part. This question assumes,
obviously, that my configuration would exceed the 30 SF
limit.
Rick, K7GM/4
aoniswan@ecuvm.cis.ecu.edu
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