In a message dated 97-04-21 19:16:36 EDT, firstname.lastname@example.org (henry gillow-wiles)
> after buying one of steve's gauges, i discovered the guys on the tower are
> WAY too loose. they are 3/16 ehs. the 2 questions are:
> 1) what should the tension be? i know it is 10% of the breaking strength,
> but i don't know what the breaking strength is.
The standard tension is 10% of the ultimate breaking strength.
3/16 inch EHS 3990 pounds UBS 400 lbs. tension @ 60 degrees F
1/4 inch EHS 6700 pounds UBS 670 lbs. tension @ 60 degrees F
> 2) what is the best way to tighten the guys? i don't want to snub one guy
> to 400lbs. in one move and have the tower lean at a 10 deg angle. do i
> think like i'm tourqueing head bolts and go in a pattern?
After ensuring that the tower is plumb, start on the bottom set of
guywires. Tighten all 3 guy wires to the same initial measureable tension -
say 100 pounds. Then step tension up to the desired figure on all cables.
What I do is to do the same thing to all guywires; i.e. adjust each
turnbuckle 3 turns. Check tension. Adjust all turnbuckles 2 turns. Check
again. As you get closer to the target tension, you can finalize each
turnbuckle without taking the tower out of plumb. One revolution of the
turnbuckle is only pulling the guywire a fraction of an inch so unless you
tighten one turnbuckle A LOT, it'll stay in plumb. BTW, you're allowed to be
out of plumb 3 inches in 100 feet.
Final step is to go around and fine tune. Now go to next level and
repeat. When finished, install your guy wire safety cable.
Be sure to allow for the ambient temperature. For 1/4 inch EHS,
120 degrees F tension should be 501 lbs.
90 degrees F tension should be 583 lbs.
60 degrees F tension should be 665 lbs.
30 degrees F tension should be 747 lbs.
0 degrees F tension should be 829 lbs.
These figures are for guys 45 degrees to the horizontal.
BTW according to the factory, the LOOS tensioner is supposedly accurate
to 3%. A test done by a TowerTalkian (N0YVY?) awhile back felt that it read
high by about 3-8%. Actually, that's pretty darn close for ham work and
certainly better than having an unknown tension. I'll guarantee that
everyone's guy wires are either way too TIGHT or way too LOOSE. This is the
cheapest, most accurate way of doing it right.
73, Steve K7LXC
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