All tower owners should regularly inspect their complete tower system – guys, guy anchors, guy wires, tower base, section bolts, turnbuckles, etc – the complete tower system. Before I climb, I visually check all I can see. When I climb, I check section bolts. And about once a year, I check guy tension and adjust as needed.
|10 Feb 2021||NW Guy||NE Guy||S Guy|
This process led to me emailing Tim W3YQ to ask his thoughts. Here is the reply:
Well, here’s my thoughts. Plumb is much more important than guy wire
tension – within reason. To have a tower in plumb, the whole
structure is in compression. It won’t fail. Just like a pencil – you
can’t smash it with a downward force, but you can snap it by bending
it in the middle.
I know of only two ways to plumb a tower. The first, best, and
easiest is to set up two transits; 90 degrees apart. Sight both
transits to the bottom of the tower then move up to the first guy
level. Get the tower straight up to that point. I usually use the
width of a Rohn tower leg as my “good enough” standard. If the
tower’s way out of plumb, you might have to mess with the other two
sets of guy wires simultaneously. Sometimes it’s really hard to pull
that first guy wire set in when the rest of the tower is fighting you.
Once the lowest set of guys is done, move up to the next set.
The tension of the three guy wires of any level will (almost) never be
equal. The only time that would occur is if you were on a perfectly
flat plane and your guy anchor points are exactly on the money.
Theoretical but not practical. Someone who adjusts all three guy
wires to equal tension almost certainly have a crocked tower. Don’t
worry about guy tension. Go for plumb. Use the tension gauge to help
you get things set “close” to the suggested tensions. Err on the side
of loose instead of tight. That 10% rule is a guideline and it’s
purpose is to prevent the guy wires from galloping. They’ll do that
in the wind if they’re much too loose. Loose guy wires, again within
reason, exert less force on the structure. Yes, when you climb, there
will be a little more movement with loose guy wires, but the tower is
not going to fall over. Too tight, on the other hand, is exerting an
extreme downward force on the tower. True that if you’re perfectly in
plumb it won’t collapse, but why go there. So just use your Loos
gauge as a guide. Never go above the 10% value on any guy wire, but
try to get close to that value on the one that needs the most tension.
Then adjust the other two guy wires for plumb and not tension. I
usually check the tension of all three and I generally find that
they’re way off from each other. That’s OK.
The second method: It IS possible to plumb by attaching a small rope
at each guy level, one at a time. Center it in tower, hang it down
through the middle of the tower, and attach a weight at the bottom.
Then stick a bucket of water for the weight to rest in. I guess you
call that a plumb bob. The water keeps the weighted rope from
swinging. It’s kind of a PITA, but it works.
So, this led to me purchasing a transit and acquiring another to be able to properly do “Method One” above. Once all the components arrive, I’ll post an update on the project.