In a message dated 6/22/2008 1:00:42 P.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> Ron: I am currently in the process of putting up a U.S. Tower MA-850
with the rotor base and will be putting a 3 element SteppIR with the 40/30
modification on top. At a 70 mph wind and the tower fully erected, I will
surely be in an overload condition if there is no margin in the
specifications.
I went through a lot of consideration, emails, and conversation before I
selected this tower because of the 70 mph wind load limitations.
I had an MA-77 calc'ed by a PE for 80 MPH and the windload capacity was
for 25 pounds. So in essence, anything you put on it will cause it to be
overloaded.
Treated very conservatively, you should get good service from your
tower. Your usage scenario sounds like it'll work.
> I think that you will find that the tower companies will be very
reluctant to talk about margin and overload. I tried, several times, and was
NOT
able to get that information. If anyone has that information, I would sure
like to get it.
Tower manufacturers are insurance driven enterprises and are averse
to risk exposure. Of course they're not going to give you any information
that might come back to haunt them. That's why you need to get an engineer
involved. The guy that UST uses is very good - you just have to pay him for
his
evaluation. The engineer will give you the information you're looking for.
Cheers,
Steve K7LXC
TOWER TECH
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