I'm putting up 100' of Rohn 55 (two level guying on pier pin). I am
thinking of using a crane to put it up for both time and safety
considerations. Cost is pretty minimal (about $100/hour - the same rate I
bill out my consulting time at!). After talking with a crane company, we
think the easiest way to go might be the following:
- Assemble all 100' of the tower on the ground
- Install rotators, mast, guy anchors, and guys (let guys drape down)
Pick the whole mess up from the top end with the crane, set it on the pier
pin, set and tension the guys, then climb the tower and disconnect the
crane.
Use the crane to place the three antennas.
The total weight of the tower with rotors and mast etc. is well within the
capacity of the crane. I'm a little bit worried about the bending on the
tower. I recall seeing that you aren't supposed to hinge up more than 30' of
Rohn 25, 40' of Rohn 45, and 50' of Rohn 55, but I can't find it anymore.
I tried to do some calculations, and it looks marginal to me, but I don't
really trust that I know what I am doing.
An alternative would be to lift up just the first 50' of tower, guy it, and
then use the crane to stack 1 or 2 sections at a time on top of that. (I'm
hesitant to try and get too long a piece of tower lined up property on the
lower part). Obviously this would take quite a bit more time (both for the
crane and for the tower climber).
Any comments or actual experience?
73 de Bill n7vm@lgcy.com
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