I'll admit up front that I don't have time to read the incredible volume
of postings to this reflector; I try to skim the subject lines and only
open maybe 5% of the messages. So maybe I missed something in this last
thread on gin poles.
The most important thing I learned is that the Rohn gin pole is not rated
for lifting 55G sections. That got my attention! What is the weak point?
Is it the mounting or the actual pole? Forgive me, but I've never
actually seen a Rohn gin pole.
I built a 45G tower summer before last. This summer I'm planning a 55G
project. I'm getting a late start, but hopefully I can get it all done
before contest season.
For the 45G, I used a gin pole that I bought from an individual who makes
them. In fact, it was someone recommended on this list, but I can't
remember his name/call. Not WB0W. It clamps around a leg with a very
sturdy looking "door" that is hinged to a piece of angle. I can't imagine
it failing under the load of a single 55G section. But then I guess I
don't have any guarantees, and I can't even remember who made it. Any
thoughts? If the Rohn gin pole is not supposed to be used for 55G, what
DO people use, other than a crane?
For the actual pole, I used a standard Rohn M200H 10' mast. Is that going
to be sufficient for 55G, assuming the mount to the tower is O.K.? Does
anyone know the yield strength for the M200H? And how does one rate the
safe working load of a gin pole anyway? I guess one could calculate the
breaking point for a perpendicular load at ten feet from the mount. That
would seem to be worst case. Then apply a 5-to-1 safety factor?
One final thing. I used rope in the gin pole for the 45G project, but I'm
seriously considering using some 1/8" aircraft cable that I have on hand.
It's quite a bit stronger, and I can fit a lot more of it on the
hand winch. Anyone see any problems with this?
73,
Tim Totten, n4gn@n4gn.com
http://www.n4gn.com
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