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Re: [TowerTalk] Rohn raised guy mounts

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Rohn raised guy mounts
From: Grant Saviers <grants2@pacbell.net>
Date: Mon, 19 Mar 2018 18:22:42 -0700
List-post: <mailto:towertalk@contesting.com>
Based on a PE plan I had done (but decided to use the standard Rohn guy anchor design) it takes a lot of in ground depth of the post or concrete mass like KC5YN used to withstand the moment of a post with 8' of clearance. My 7' clearance 8" sch 40 pipe post holes were to be 4' square by 7.5' deep for a much bigger tower. I have seen posts not set deep enough that were leaning get saved with a back guy to a concrete deadman, but that kinda defeats the whole idea. IMO this is PE territory to get a stable design both for the needed soil resistance and the beam strength & deflection. The guy pretension is present 24x365 also, so freezing and ground water influences could be significant.

Grant KZ1W

On 3/19/2018 14:53 PM, Fred Keen via TowerTalk wrote:
We installed raised guy posts similar to Eds. I bought 8" wide flange beams (I beams) 12' long 
and had 3/4" rods 36" long welded to the front and rear (three each side) of the flat 
faces of the beams about 8" apart on the lower 3 feet of the beam. We then set the bottom 4' 
of the beam into a 4' x 4' x 4' hole and and filled with concrete.
This allows me to mow with approximately 8' height clearance around the base.
The tower is 70' Rohn 45, with guy connections at 33' and 66'. The top 20' of 
the guys are phillystran.It supports a Force 6BA 40-10meter yagi, 80 meter 
rotatable dipole and 6meter yagi.
Note, you should take into account the guy spacing as shown in the book going 
to the ground will be different for the top and middle guys. I would use the 
dimensions for the top guys. This you can do with a scaled graph chart.

Good luck with your venture.
Fred KC5YN




     On Monday, March 19, 2018, 12:17:08 PM CDT, Ed 
Sawyer<sawyered@earthlink.net>  wrote:
The ones I have seen were home made. 12 or so ft of building construction
grade steel I beam with a few guy attach holes drilled near the top of one
end and a couple of holes for some steel rods to be passed through on the
bottom end.  The lower 4 ft or so is buried in concrete with the steel rods
going through at right angles to the I beam.

Ed  N1UR

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