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[Towertalk] 45G foldover

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Subject: [Towertalk] 45G foldover
From: (jljarvis)
Date: Mon, 1 Jul 2002 05:27:46 -0400
I just took down my 45G foldover.  It was house-bracketed,
and constituted the world's largest wind chime, in gusts.

It served quite well to provide cold weather access to
antennas at modest heights, here in VT.

The probable reason that hams have lost many of these is
overloading.  As they're out of production, I don't know
if you can get any load-calculation data from Rohn.

It uses a DL-1500 winch.  Assume, for the moment, that the
winch is the weak link in the system.  You need to calculate
the load above the fold, and see how that plays out.  That
means that you need to know the weight and placement for 
everything out there.  

In my case,  I folded at 22', to provide a good working height
above my flat roof.  The tower went up 26' above that, with
another 12' of mast projecting.  If I remember correctly, the
winch cable was bearing 970 lbs...or about 2/3 of its rating,
when I took the 18,000 lbs of torque, divided it by the back-
boom lever arm length of....what was it, 18'?

Another reason these things fail is tipping them beyond 90
degrees.  Above horizontal, the winch load goes way up, and the
back boom load becomes compressive.  

One other characteristic...they're heavy as all get-out.  You can't
raise or lower them with a ginpole.  You need a come-along to do
it safely.  And you have to do it piecemeal....the complete ass'y is
too heavy for 2 people to handle.  

I agree with Steve....put up a simple tower.  Guy it well.  
Sleep nights.


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