In a message dated 11/12/2006 6:43:07 A.M. Pacific Standard Time,
towertalk-request@contesting.com writes:
> Hi. Finally started stacking my 110' Rohn 55 tower. We have 40' up with
two
sets of temporary guys (AB-577 stainless guys, actually, which work nicely
for temps.) The permanent guys are attached to the guy bracket at 33' and
are ready to be connected to the anchors and tensioned. The guys are
Phillystran, but with EHS leaders at the bottom. I'm using Big Grips.
> I'm curious about the detailed sequence for tensioning the guys. I have
one
Klein grip and one come-along. I also have a Dillon Dynamometer and a Loos
gauge. I think I understand the general sequence for tensioning one guy:
> 1. Attach one end of come-along to guy anchor
2. Attach other end of come-along to Klein grip
3. Attach Klein grip to EHS ahead of where the big grip is likely to end
4. Unscrew turnbuckle most of the way, leaving about 1-2" of thread (I'm
using 12" turnbuckles)
5. Use come-along to tension the guy near the final pre-tension figure.
6. Install shackle, thimble and big grip on free end of guy.
7. Release come-along.
8. Use turnbuckle to reach final pre-tension.
> As for determining tension, my plan is to put the Dynamometer in line with
the come-along and use it in step 5 and to calibrate the Loos gauge. That
way, I can use the Loos gauge to determine tension after I've removed the
come-along and Dynamometer.
The sequence is fine. The Loos gauge is pretty accurate as is but no
harm in checking it against your Dillon. Actually I wouldn't even bother with
the Dillon. The Loos is accurate enough and all you have to do is hang it on
the guywire without messing around with the comealong et al.
You can pull a guywire by hand enough to put a little tension on it. Do
that with all 3 and then take a measurement. For pre-tension, you just want
all of them to be the same regardless of real tension. Once the tower is
plumb, from there just do equal turns of the turnbuckles. It's easier if
you've
got someone on each guy and tell them "4 more turns" or whatever until you've
got the desired tension. I usually don't do the final plumb-and-tension until
the tower is done.
> What I'm not sure about is how to approach doing all three guys. If I
tension the first guy near to the final pre-tension figure, as in step 5,
then it seems to me that the tower will be pulled off plumb, and I might not
be able to pull it back by tensioning the other guys.
See comments above. Install the first one with a little tension and the
other 2 the same way. Then go back and put some measurable pre-tension on
them. You won't have enough initial tension to worry about.
> But if I don't put
enough tension on the first guy, then I might run out of thread on its
turnbuckle. It would seem like this is an iterative procedure, and that it
might require unclamping and retensioning each cable several times.
That's where 3 comealongs and 3 grips comes in real handy, but it's not
absolutely necessary. You'll have enough scope in your turnbuckle to handle
it. Don't put the PreFormed grip on all the way. Just wrap it 1/2 way to begin
with. That way there'll be enough holding power to hold the tower up but
it'll come off easily if you have to move the guywire. I don't do the grip
final
wrapping until the tower is finished.
> But to
do that, I'd have to install, undo and reinstall the big grips several
times, which is not good.
You can unwrap the grip twice, giving you 3 tries to get it right.
That's usually enough.
> Am I worrying needlessly about this (i.e., there will be enough turnbuckle
thread) or is there a trick to this?
Yes, you're worrying a little too much. It's got a little bit of a
learning curve but it'll be close enough after you've been thru an iteration
or two and everything's fixable so you'll eventually be successful.
Cheers & GL,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
Cell: 206-890-4188
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