In a message dated 8/5/2007 11:27:19 A.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> I'm developing a long-term proposal for a second tower and antenna. My
first
tower is a UST 72' crank-up with Force 12 yagis for HF and 6M. For the new
tower, I would like to put a StepIR MonstIR up at least 100 feet. I live in
a 70 mph wind county in rural NW TN.
> After looking at some of the internet offerings, I have a question. What
kind of tower do I need ? This is truly a monster antenna with 70 foot
elements - about as long as my present tower is tall ! This will produce
tremendous torque when rotated (or just standing still in any breeze). I was
anticipating using Rohn 45G for this but looking at their web site, it looks
as if 55G is even undersized for this. The University of Michigan ARC has 30
feet of 55G mounted on the roof of a building with this antenna ! WOW! Nice
club ! There is a contest station in 6Y that has not one, but 2 of these
dream antennae mounted on Rohn 45G in a stack ! Amazing.
I've installed 4 MonstIRs and they've all been on 100 feet of 45G. It'll
work just fine. If you're concerned about the wind induced torque, use a
star bracket for the top set of guys. That way the tower won't move at all.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
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