I have a 155' of Rohn 45G at my qth with 4 sets of 1/4" EHS (with
Insulators) torque to 590 lbs and there is no slack in the lines. 73's Fred
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Dale Martin
Sent: Wednesday, April 25, 2007 11:24 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Tower guy wires / EHS size
Thanks, Frank. Good info.
I'm still curious, though. Is there that much slack in 1/4" EHS tensioned
to 400 lbs. -- 10% 3/16" strength? Is it the weight of the cable
introducing a sag that 400 lbs. tension cannot remove that wears away at the
hardware?
73,
Dale
>
> Dale,
>
> Using 1/4 inch EHS rather than 3/16 inch EHS will not be a problem.
>
> Initial guy tension is normally set at 10 percent of its
> published breaking strength, with upper and lower limits of
> 15 and 8 percent.
>
> Guy wire tension less than 8 percent places excessive wear on
> guy attachment hardware as the guy slackens and tightens
> repeatedly during wind events. There have been many
> documented cases of guy attachment hardware failure as a
> result of excessive wear caused by inadequate guy tension.
>
> Guy tension is excess of 15 percent of breaking strength
> reduces the useful load capacity of the tower by placing
> unnecessary vertical loads on the tower.
>
> 73!
> Frank
> W3LPL
>
> ---- Original message ----
> >Date: Tue, 24 Apr 2007 13:04:03 -0500
> >From: "Dale Martin" <kg5u@hal-pc.org>
> >Subject: Re: [TowerTalk] Tower guy wires / EHS size
> >To: <K7LXC@aol.com>, <towertalk@contesting.com>
> >
> >
> >
> >I'm curious, Steve, where 1/4" EHS is used in place of
> recommended and
> >spec'd 3/16" EHS, does one tension the 1/4" EHS to 400 lbs. as one
> >would do with 3/16" or to whatever tension 1/4" is rated for?
> >
> >Looking from another aspect, is the 400 lbs. tension specified when
> >using 3/16" EHS on a Rohn 25g based on the tower type/heighth where
> >3/16" EHS conveniently has a stength of 4000 lbs and the 400 lbs
> >tension is just right for the tower? Or should the tension
> be 10% of
> >whatever guy wire size strength is being used...e.g., 670
> lbs. based on 1/4" EHS strength of 6700
> >lbs.?
> >
> >73
> >Dale, kg5u
> >
> >
> >>
> >> In a message dated 4/23/2007 9:03:02 A.M. Pacific Daylight Time,
> >> towertalk-request@contesting.com writes:
> >>
> >> > I am in the process of erecting a few towers at the new
> >> QTH and have
> >> > a guy
> >> wire size question. Two of the towers will be Rohn 45 @
> >> 100' and the third
> >> will be Rohn 25 @ 100'. They will all have multiple yagis at
> >> various heights on them, so not just a top mounted
> antenna. The Rohn
> >> book indicates that each tower should be guyed at three
> elevations
> >> and the bottom two guys should be 3/16" EHS.
> >>
> >> > QUESTION: I have LOTS of 1/4" EHS and guy grips. Is
> the 3/16"
> >> > mandatory
> >> to
> >> meet the specs (as in the 1/4" is too heavy) or - is the 3/16"
> >> simply suggested (as in the 1/4" is not necessary but acceptable)?
> >>
> >> While the LXC Prime Directive to "DO what the
> manufacturer says"
> >> still applies, what you're proposing is a little bit of
> >> over-engineering (which is not discouraged, BTW).
> >>
> >> The capacity of any tower is a function of its leg
> strength. By
> >> using bigger guys you'll be putting more compression on
> the legs but
> >> at the heights you mentioned, it's not a big deal. 45G will go to
> >> 300' and 25G will go to 200' so you're not overstressing anything.
> >>
> >> Cheers & GL!
> >> Steve K7LXC
> >> TOWER TECH -
> >> Professional tower services for hams
> >> Cell; 206-890-4188
> _______________________________________________
>
>
>
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