In a message dated 12/30/2007 7:32:04 A.M. Pacific Standard Time,
towertalk-request@contesting.com writes:
> I guess another question would be, since I was thinking of leveling it
with a bubble level, but I dont have one that is over around
a 6" long. Will a plumb bob through the center of the first section be
accurate enough to make the tower straight as I go up in
height to say 80 feet or so?
A bubble level is fine. I use one of the 8" or so variety - it's close
enough. Industry standards let you be out 3 inches in 100 feet and still be in
spec.
If the bottom section is in concrete, then that's place to start. If
it's plumb, then the rest of the tower is easy. Stack the sections and then
use
your level at the first set of guys. For subsequent sections, just look up
each face. It'll be pretty obvious when it's in plumb and when it's not. Feel
free to use your level at each guy level as you direct your ground crew which
guys to tighten.
> I was rethinking the vertical leveling and thought I might just tie a
string at the center of the top of the section (ten foot
bottom section) I am going to cement in -
> tie a rock or something to it
eyeball it to be in the center of the section
at the end of the string at ground level
then cement it in
> But then remembered the higher I go
the more off center it will get if I am off at all at the bottom.
I use this all the time for self-supporting towers since the only thing
plumb is the side of the leg. You don't cement it in. Just let it dangle with
a
weight on the bottom of the string and sight thru the face to the opposite
leg.
BTW the concrete base requirements for a guyed tower aren't as critical
(e.g. undisturbed earth) as for self-supporting towers. The only thing the
guyed tower base does is prevent the tower from sinking. There is no
overturning moment on the base like there is on a self-supporter.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
Cell: 206-890-4188
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