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[TowerTalk] Tower anchor placement question.

To: <>
Subject: [TowerTalk] Tower anchor placement question.
From: "Cliff" <>
Date: Wed, 8 Dec 2004 18:12:22 -0500
List-post: <>
Hi all,
I'm in the process of putting up a Rohn 25 tower, but have some concerns
about placement of the anchors. I would like to have some qualified
opinions on this layout. There are a number of reasons that led to where
I have placed my tower, which I'll not bore everyone with, but instead
I'll describe the placement.
The tower height is not exactly set, but will be a maximum of 95 feet
above ground, including a tapered top section. It may be one or two
sections shorter, depending on how tall the forest around me really is
(can't exactly determine from ground level.)   The terrain is a ridge
with the tower placed near the ridgeline.   The tower base is a full
straight section set in 4'6" of concrete (with 6" of gravel below for
drainage of the tower legs that stick out the bottom of the concrete.)
My questions center around the placement of the guy anchors.   I am
using AB Chance 816 anchors - 66" long, 8" diameter auger, 1" shaft,
12,000 lbs pull strength in local soil, so they should be adequate.
There are to be 3 guys at 3 different levels.  At present, I am planning
for 31', 63' and 90'.   The 31' is necessary for one set of wires to
clear the roof of my house.   
Anchor #1 is placed at 180 degrees, 79.5 ft from tower and 56 inches
above tower base height.
Anchor #2 is placed at 300 degrees, 90 ft. from tower and  52 inches
below tower base height.
Anchor #3 is placed at 60 degrees, 52.33 ft from tower and 7 inches
below tower base height.
This seems to be the optimum placement for the terrain. #1 is placed in
the front yard forest, and is movable.  #2 is placed to allow sufficient
clearance to drive a vehicle under the lowest guy wire.
Here's the real question.  Anchor #3 is placed as close to the property
line as possible, but only 52.33 feet from the tower.  This distance is
only about 55% of the height of the top guy wire.  What is the opinion
of the knowledgeable on this location?   Can/should I compensate for
this by varying guy wire tension around the tower?  Any other
I do have a tension gage to use on the 3/16" EHS guy wire that I am
Cliff, AG4XR

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