Lot's of good thoughts fellas.
I would have all the prep work done or ready to be done prior to the lift.
To answer a couple questions:
1 - Guy spacing is not an issue, the anchors are already out the required
distance and have more than enough concrete. I had planned on side mounting
and wanted to be sure I had the clearance for turning the beams.
2 - I plan on splicing guy's with thimbles or insulators. The current onces
are a combination of Philly and EHS. Once the crane is attached I can remove
the guy's from the ground anchor and splice the required length and I'll be
ready for the re-install.
3 - I will build the new 40' of tower horizontally, install the guy bracket
and guy's and use a second smaller crane to put it place. If I a 42'
terrain forklift is cheaper, I'll go that route. It doesn't take long to be
sure the tower is plumb and tension the guys.
4 - Tag lines will be a must to keep the tower from twisting. A non-windy
day will be the trick. Around here (the 3d windiest city in the USA), it's
difficult to plan for a non-windy day, but it can be done.
The crane guy's I use are pretty good and have a good idea what needs to be
done. Lately they've been installing the great big wind mill's here in the
panhandle
When I originally installed the tower, the first 40' was installed with a
42' terrain fork lift (my neighbor was using one so I borrowed it for an
hour). The guy's were pre-attached. I just left plenty of extra length on
the guy's so I had some working room when they were attached to the
turnbuckles. Then the big crane came and we installed the top 37' the same
way. I even pre-installed the rotor, mast and coax cables. We just lifted
it in place. The tower stayed fairly vertical and it was easy for the
rigger to attach the top portion to the bottom portion.
What has changed in this equation are the antennas. It would just make
things so much simpler and consume less time if I could leave the antenna's
in place. With all the prep work I'll bet I can get this project done in
about 4 hours. The original install took about 5 hours which included
installing the top 37' of tower, tensioning guys and installing two antennas
(using a bucket attached to the crane cable).
I'll post some pic's on qrz.com later this evening of how I recently
replaced the Delta 240 with a Delta 240/230 with the crane/bucket.
Rich - N5ZC
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Richard Thorne
Sent: Monday, November 18, 2013 9:35 AM
To: towertalk@contesting.com
Subject: [TowerTalk] Tower Lift (with crane) with Antenna's Already
Installed
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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