Frederick M. Mott wrote:
>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
>
>
No slack?
If there is no catenary in the guy lines, please give us your method of
defying the Law of Gravity!
Don
N8DE
>-----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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>>http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>
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