Blake:
I beg to differ with you.
Using TIA/EIA 222-F wind loading criteria and 70 mph wind velocity (min.
recommended) a 40 foot section of Rohn, 25g un-guyed and cantilevered will
develop a moment at the base of 7200 ft-lbs at the base. This is without an
antenna load, just the tower itself. The published allowable moment for 25g
,by Rohn, with a 1/3 increase for wind loading duration is 6,720 ft-lbs. At
40 feet it is clearly overstressed. How do you say that this is ok and that
Rohn fully supports this?
Regards
Lonberg Design Group, Ltd.
Hank Lonberg, P.E.,S.E. / KR7X
President
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Blake Bowers
Sent: Saturday, January 29, 2005 12:53 PM
To: TowerTalk@contesting.com
Subject: Re: [TowerTalk] Rohn 25
Actually, Rohn fully supports the R25 up to 40
feet as a self support.
Aside from that however, 60 feet they do not support,
and supporting an inverted V would be an absolute
no-no.
I have seen R25 at 60 feet self supporting a lot
however, and they do fine, again without an inverted
V pulling on it.
> I'd guess about 12 feet :)
>
> The 25 isn't designed to be free standing, though I've seen them up to
> 30 or so with no real trouble if the base is good.
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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TowerTalk mailing list
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
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