In a message dated 97-09-11 01:58:09 EDT, firstname.lastname@example.org (Penelope
Barbour Jones) writes:
> I AM CURRENTLY INSTALLING A 70 FT ROHN 25G TOWER AND
> HAVE A COUPLE OF QUESTIONS.
Hi, Larry --
First of all, reach over and turn off your "caps lock". Thanks.
> WHAT IS THE CORRECT PROCEDURE FOR APPLYING TENSION TO THE GUY WIRES? CAN
> THEY BE TOO TIGHT, TOO LOOSE, WHICH IS WORSE? I'M USING 3/16 EHS
> STEEL GUY WIRE. THERE WILL BE 6 WIRES, 3 @ 32FT 3 @65FT.
The best thing to do is to have a guy grip and comealong attached to
each anchor. Then you can plumb the tower and put the guys at an initial
tension. Then you can go around to each one and adjust them all equally (4
clicks, etc.). The most practical, accurate and cheapest way to measure the
tension is with a Loos guy tensioner. TOWER TECH has them for $39.00.
The guys should terminate in a turnbuckle at your anchor. After getting
all the guys at spec (400# for 3/16 inch EHS - 10% of ultimate breaking
strength), you adjust the turnbuckles until they take the tension. Repeat on
the upper set having done the bottom set first.
> HOW IMPORTANT IS IT TO HAVE A BUSHING IN THE TOP SECTION OF TOWER? MY
> ROTATOR MANUAL (A HAM 3 ROTATOR) SAYS TO USE ONE. MY PROBLEM IS THAT THERE
> IS NOT CLEARANCE ENOUGH TO HAVE ONE. THE ID OF MY TOP SECTION (A ROHN
> 25AG3) IS 2.100, MY MAST OD IS 2.000 LEAVING ONLY .100 CLEARANCE (.050 PER
> SIDE). IS THIS TOO MUCH CLEARANCE TO GO WITHOUT A BUSHING? TOTAL WIND LOAD
> WILL BE ABOUT 10 SQFT.
Don't worry about a bushing; it just limits lateral mast movement. Your
AG3 will do the same thing.
73 and GL, Steve K7LXC
TOWER TECH -- professional tower supplies for amateurs
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