The 80 percent figure is one component of the wind load rating of the tower
and guy system. One could re-calculate the wind load rating resulting from
a change in this component. I could do this but it would take a long time
since my physics is quite rusty. But, the point is that the guy system
could be beefed up to achieve the same wind loading with less radial
distance of the anchor to the tower base.
Keith
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Darrough
Sent: Monday, September 20, 2004 4:27 PM
To: Tower (K8RI)
Cc: Bryan; towertalk@contesting.com
Subject: Re: [TowerTalk] Concrete anchors
A friend of mine who does commercial towers told me that guy anchors should
be set out 80% of the height of the tower. That means that at 120' tall, you
should have your anchor points out 96 feet from the center of the tower
base.
You ought to check with Rohn about that, because as we all know, different
soil densities and "wetness" can drastically affect how well your anchors
perform. Another resource would be a local Engineering firm, specifically a
Civil Engineer. If you know anyone in that line of work, you might start
there.
73 Jim Darrough, KI7AY
On Fri, 17 Sep 2004 16:26:58 -0400, Tower (K8RI) <tower@rogerhalstead.com>
wrote:
>
>
> >The drawing I have for the gac305 anchor shows them angled but doesnt
> >give any hints on >how to do it. I know I need the hole to be 3x3x4
> >but from there I'm not sure what I need to >do to get the anchor in
> >the right position.
>
> "As I recall" (which means you still need to look it up in the ROHN
> book) the anchor comes out at 45 degrees and is far enough from the
> tower to point between the the top two guy sets.
>
> >I have a yard that measures 180' long by 80' wide. I'm looking to
> >install a 120' rohn 25g. Can >I run 4 sets of guys off the tower to
> >make up for not having the 120 deg span?
>
> 120 feet on an 80 foot lot? You must not have neighbors, or no
> setback rules. Even with 4 point guying you need the anchors much
> farther out than you can get them for a 120 foot tower on an 80 foot
> lot. At a120 feet I'd say you need 100 feet from the tower for each
> guy anchor. You can get by with a bit less, but that 120 feet on an 80
foot lot scares me.
>
> Roger Halstead (K8RI, EN73 & ARRL Life Member) N833R, World's Oldest
> Debonair (S# CD-2) www.rogerhalstead.com
>
> Thank you for your help
>
> Bryan
> _______________________________________________
>
> 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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>
> _______________________________________________
>
> 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@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
--
Jim Darrough
ARS KI7AY
Springfield, OR
CN84nc
http://www.ki7ay.com
_______________________________________________
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
_______________________________________________
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
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http://lists.contesting.com/mailman/listinfo/towertalk
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