I have not picked up Rohn 55 but on a similar tower, if there is a concern
for bending, pick it up just above the 2/3 height point. Assuming the
rotor and mast isn't a HUGE weight, I'd pick at the 70-75' region. There
is no real reason to want to pick from the very top. It will hang very
nicely and can be brought vertical easily with the guy wires.
If you really want to save time climbing (or are worried about it) run a
75' sling/rope inside the tower and tie it near the bottom. Let the crane
hook on where the sling comes out the tower at the 75' mark. When safely
vertical and guyed, just untie the bottom knot and the crane should be
able to pull the rope free easily and no one need climb.
73 Don
VE6JY
On Fri, 1 Feb 2002, Bill Ralston wrote:
>
> 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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> same place that pays for the hosting of this list: The eHam Store.
> Order online at http://store.eham.net.
> -----------------------------------------------------------------------
>
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________________________________________________________________________
Where do you get ICE bandpass filters & beverage matching boxes? The
same place that pays for the hosting of this list: The eHam Store.
Order online at http://store.eham.net.
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