[TowerTalk] Earth Anchors

[john at kk9a.com]

I am surprised you did not mention that you can purchase Rohn anchor rods
at http://www.texastowers.com . They are designed to be used as tower
anchors and can be shipped anywhere in the U.S.

John KK9A


To:	ed.n3cw at gmail.com, towertalk at contesting.com
Subject:	Re: [TowerTalk] Earth Anchors
From:	TexasRF--- via TowerTalk <towertalk at contesting.com>
Reply-to:	TexasRF at aol.com
Date:	Tue, 17 Mar 2015 13:39:51 -0400


Ed, when multiple guys are connected to an anchor, the resulting forces are
 resolved to single angle.
Knowing what this angle might be is another matter though.

There are guidelines in the Rohn catalog that might help. Their
pre-engineered anchor designs assume you have the anchor placed 80% of the
tower
height away from the base. Then depending on the number of guys and where
they
are connected to the tower, the anchor rod angle is specified. For 25G, this
 varies from a minimum of 37 degrees to a maximum of 50 degrees.

If you are using a different base to anchor distance these numbers would
also be different. You can see that using a mid range number of say 43
degrees  you would only be off by about 6 degrees and that seems close enough
to
your 5  degree number.


The Rohn designs have the top guy connected about 5ft below the top of the
tower. If you connect higher then the optimum angle would be a little
higher. If  you place the anchor less than 80% of the height, then the
optimum
angle would  also be higher.

All of this is also based on the prescribed guy wire sizes preloaded to 10%
 of the rated breaking strength.

Hope this is helpful.

73,
Gerald K5GW
GM Texas Towers