Jim,
I didn't copy the linearity part of the prior post as I didn't want to induce
any confusion. "snaking" (linearity) and "twisting" (angular rotation) both
have their own specs in EIA-222-D.
6.1.2.2 Linearity - For guyed structures, the maximum deviation from a
straight line between two points shall not exceed one part in 1000, (1.2 per
100 ft.)
On a large tower to check all these specs correctly in a reasonable amount of
time likely requires a transit (as Paul noted). I only know one ham that owns
a transit and knows how to use it. Been a long time since I used one in
physics 101 and I wasn't real good with it either :-)
To me, pragmatism rules. For 100 foot towers with 3 or 4 guy wires per leg
then I think by taking ones time and carefully checking plumb and guy tension
you are going to be just fine. If that wasn't true almost all of us would
have failed towers because I bet very few (self included) have had their
towers sighted properly and are perfectly within the EIA-222-D specs. Heck, I
bet most folks have never checked guy wire tension - but that's an entirely
different thread designed to sell Loos gauges :-)
With all that, I tend to over do things a bit so if I were putting up several
towers at once, or perhaps one big one (FWIW I define "big" as over 140 feet
for hams), I'd probably seek out a professional to sight them and get them
all perfect. I bet with a bit of poking around you can find someone who would
have the right gear and do it at a reasonable cost. I looked into this a bit
just to inform myself when I started building in NC. The rental cost on a
transit was not prohibitive given the cost of towers in general.
$0.02 FWIW YMMV
Mark
KI7WX
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