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Re: [TowerTalk] Engineering Help wanted

To:,, Michael Ryan <>,
Subject: Re: [TowerTalk] Engineering Help wanted
From: jim Jarvis <>
Date: Tue, 02 Jun 2009 11:59:47 -0400
List-post: <">>

First, good points were made by Dave, K6LL and Bill, W2AY.   Namely,   
that Rohn
spec's 2 s.f. load no more than 30' above a house bracket.   You've  
overloaded the
tower with the TH6.   It's testimony to the conservatism of Rohn's  
specs that you've
had no problems.  (and I've done some similar things, over the years,  
and gotten away with them.)

Second, Bill's point about water in the tower legs is extremely  
important.   Mike Ryan
says it shouldn't be a problem, and indeed it shouldn't, IF, and it's  
a big if, you haven't
accumulated water in the legs.   I took down a 25g foldover last  
Fall, and ultimately had
to cut the legs and pull it over, because it wasn't safe to work on,  
due to water damage.

My recommendation is to drill a 1/16" hole in each leg, 3-4 inches  
above the base, and
see if you get water out.   If not, then it's probably fine to climb  
and work on.   If you do get
a steady leak or stream,  you have a structural unknown.

If your tower climber is not comfortable with working the unguyed  
structure,  I recommend
temporary guys (steel, not rope!) at the top, while he strips off the  
antennas.    However,
you should be guided by his comfort zone.

As for putting up a lighter tower, and keeping the TH6... bear in  
mind you're transferring the
overload from a known, conservative situation, to an unknown one.     
I would be inclined to
replace the 25G, on the same base,  assuming that you can verify  
there's no water in the legs.



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