I recently bought and installed a 70' aluminum Universal tower to hold a
XM-240 40 meter beam. If you look at the installation drawings you see a
man walking up the tower. My contractor laughed pretty good at that
illustration, as did I. I decided to use the falling derrick method of
raising the tower. I bought a Rohn 25G tiltover base plate and 3 10'
sections of 25G for the derrick. I mounted the plate on the same
platform as the tower. I plan to use the winch on my 700lb ATV to pull
the derrick down and the tower up.
I have not done any calculations, as it is easier to ask you experts and
civil engineers on this reflector. If nobody has the answers I will
crack open the right books and figure it out. It looks like rather
simple math based on weight of the tower, beam weight, rotor weight,
mast, overhang past attachment point. Here are the facts.
70 foot alum. Universal tower HD21-70 322lbs
30' rohn 25 as derrick.
XM-240 beam 55lbs - mounted just above tower tube, little extension
beyond tower top
6' alum mast 5lbs
DX1000 Yaesu rotor 10 lbs, mounted 3 feet down in top section
steel line from 30' point on derrick to 40' point on Alum tower.
I am open to SWAG's as well as calculated answers. If I missed any
critical data, let me know. I know that calculating the sole tower
weight beyond the 40' foot attachment is not known, but taking 1/3 of
the tower weight as an estimate is close enough. based in the size of
the sections below this point, probably conservative.
any ideas from you geniuses out there?
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