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Re: [TowerTalk] Request for Advice - Rohn 25 vs TRI-EX HZN 471

To: Bruce Ward <>
Subject: Re: [TowerTalk] Request for Advice - Rohn 25 vs TRI-EX HZN 471
From: Joseph or Ruth Patrick <>
Date: Sun, 19 Feb 2012 07:17:11 -0800 (PST)
List-post: <">>
Hey Bruce

Your friend is an engineer although a civil engineer that would be the first 
place I would ask. 40' of basically free standing 25G sounds great until you 
have to climb it or a big storm comes by. What are your minimum height 
requirements?  I am not an engineer so I really can't give you better advice 
than to draw it and get the engineer to say OK. Yeah even engineers make 
mistakes. Good luck. I will be interested in your final solution.
 73 DE K4XZ Joe Patrick
God Made Man
Sam Colt Made Them Equal 

From: Bruce Ward <>
Sent: Sat, February 18, 2012 6:53:08 PM
Subject: [TowerTalk] Request for Advice - Rohn 25 vs TRI-EX HZN 471

I am setting up a tower (my first) to get internet service.  The 
antennas will be less than 2 square feet of wind loading combined and 
could be even less using 2 11x14" grid antennas.

My plan is to build a 10'x10' 9' to 10' tall block building on a slab 
that is larger in all directions.  This building will will have a 
concrete roof with rebar and wire in all concrete.  The blocks will have 
rebar and concrete in every cell.  The structure will use 12  to 15 
yards of concrete plus 400 concrete blocks providing an over 45,000 
pound base for the tower.  I have a civil engineer friend who will be 
involved in the final design of the building.  The building is dual 
purpose, it will provide a secure home for my servers and a stable base 
for the tower.

Now for the difficult part, I do not have room for guy wires.

I am trying to decide between two options

1. I have 9 full and a top section of Rohn 25G in my yard waiting to be 
be installed.  Currently Rohn rates the 25G for freestanding use up to 
40' with 1.4 square feet of wind loading.  From reading online it sounds 
like Rohn 25s have been used for decades even higher without guy wires.  
I do not want to risk stretching beyond Rohns specifications.  I have 
access to 40' lengths of 8" pipe. If I go with the Rohn 25G my intention 
would be to embed a  40' section of the 8" pipe into the building and 
bracket to that pipe up to 35' or so then have the tower extend another 
35' to 40' above the pipe.  All the metal would be isolated from the 
ground and properly guided with a ground rod to avoid corrosion issues.

2. There is a TRI-EX HZN 471 available locally.  I would have jumped on 
this one earlier but it is worth more the the current owner than it is 
to me.  This is a 70' (71'?)  crank up tower with a motorized winch. The 
motor is broken and would need to be replaced.  The tower is free 
standing with the exception of three diagonal pipe braces that connect 
from the top of the bottom of the 4 sections to the ground around 10' 
out.  I like that this tower is freestanding and I believe I could do 
away with the braces if I bracketed the tower at the same location to a 
sufficiently strong structure.  If I used this tower I would likely 
build a 3'x3' column of solid concrete into my building and place the 
tower on top.

I would very much appreciate any suggestions and advice.

Thank you.


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