i would not pull up more than about 60' of rohn 25 no matter how many people you
have. i would expect that at 90' with lights and wires you would fold over the
legs of the bottom section or fold the whole thing in the middle, probably as it
twists and tries to turn sideways... i'm not sure which spot would go first...
its just too heavy to support its own weight at an angle at that length unless
you are very lucky. i would put up 50' or 60' on the hinged base then add the
top 30' with the gin pole. this gives you a fairly solid base with 2 sets of
guys before you have to climb.
Eric Schurman wrote:
>
> >Don't even think of pulling up 90 ft of tower on a simple hinged base.
> >The forces at the BASE are ENORMOUS. The SAFEST solution is
> >the old fashioned gin pole and rope assembly method of stacking
> >one section at a time, starting with a temporary set of safety guys
> >at 10 to 20 ft and permanent guys (3/16 inch EHS) at 30, 60, and 90 ft.
>
> Hm... That's too bad. Do you think this is just impossible, even with many
> people (up to 25 or so) trying to distribute the load across the tower? I've
> also talked with the guy funding it and realized that it only needs to be
> 80feet tall. There is a real push to avoid having to climb it, but if it
> can't be helped, it can't be helped.
>
--
David Robbins K1TTT
e-mail: mailto://k1ttt@berkshire.net
web: http://www.berkshire.net/~robbins/k1ttt.html or http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net
List Sponsor: Champion Radio Products - We'll be at the Dayton Hamvention
with all of our safety equipment and other products. Stop by booth #559 and
say hi.
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