[TowerTalk] Tower Lift (with crane) with Antenna's Already Installed

Steve Maki lists at oakcom.org
Mon Nov 18 11:02:47 EST 2013


It's perfectly feasible, but depending on your plan for handling the guy 
wires, may not save all that much time over dropping the mast with 
antennas into a short larger pipe stuck in the ground, dropping the top 
section, and popping up 4 new sections one of which has the new guy set 
already attached, and dropping the loaded mast back into the tower (all 
done with the crane).

If you do it *your* way, whatever your guy plan is (extending the 
existing guys and just adding new ones for the the new lower bay(s)?) 
you should have absolutely Everything possible prepped in advance.

And the crane should be large enough so that if the tower spins while 
it's hanging the antenna elements don't bang into the crane boom.

A calm day would be nice (not like today here in the Midwest).

-Steve K8LX

On 11/18/2013 10:34 AM, Richard Thorne wrote:

> I have a 77' Rohn 45g tower installed with a large tribander and 4 element
> 30/40 combo installed. The tribander is about 1' above the tower and the
> 30/40 combo is 6' above the tower.  Total mast out the top is 15' or 9' of
> mast above the top antenna.
>
> I want to take the tower to 117'.
>
> What I would like to do is leave the antenna's installed and have a crane
> lift the entire tower up 40+ feet then slip 40' of tower below and reset the
> original 77' on top of the new 40'.  I could remove the antenna's if
> necessary, but that add's crane time.
>
> The crane would attach at the very top of the tower.
>
> My estimates have about 225 lbs above the top of the  tower (the crane
> attachment point) and 600 lbs for the tower and rotor and a % of the mast
> below the crane attachment point.
>
> So the question (I'm an accountant not an engineer) will the tower stay
> straight up and down or will it tilt due to the weight above the tower/crane
> attachment point?  I honestly don't know what the affect will be since the
> antenna's have the weight distributed along the boom, not directly above the
> fulcrum.
>
> I'm also assuming that the double bolt system on each tower leg will hold
> the tower together safely.
>
> This may sound crazy to some, but it's difficult to get tower help. I've had
> very good success with the local crane company.  I get a crane operator and
> a rigger for assistance.  That's how I installed the tower/antennas in the
> first place.  It's safe and quick.
>
> You can check out the tower on my qrz.com page.
>
> Thanks,
>
> Rich - N5ZC



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