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[TowerTalk] Rohn 55 vs. Rohn 45

To: "'\"TowerTalk\"'" <>
Subject: [TowerTalk] Rohn 55 vs. Rohn 45
From: "Joe Subich, K4IK" <>
Date: Thu, 13 Jan 2005 01:20:02 -0500
List-post: <>
OK, here's a toss up that should generate some real discussion: 

Rohn 45 and Rohn 55 have essentially the same face width and 
the same cross bracing.  The Rohn 55 has slightly thicker wall 
side rails -- the center to center spacing of the side rails 
is only 1/4" more (about 1.5% larger) than that of Rohn 45. 

I am confused when comparing the Rohn 45 and 55 catalog specs  
for 100' at 110 MPH.  The 45 design uses 1/4" EHS at the top and 
3/16" for the intermediate guys ... it is rated for 7.9 sq. ft.  
The 55 design uses 5/16" EHS at the top, 1/4" EHS in the middle 
and 3/16" EHS at the bottom ... it is rated for 15 sq. ft.  The 
guy anchors for the 55 design have about 25% more concrete (.84 
cu yd vs. .67 cu yd).   

I can't imagine the difference in rated capacity is explained by 
the modestly larger side rails. Does this indicate that Rohn 45 
could safely be loaded more heavily if the guy wires were upgraded 
(e.g., to the Rohn 55 design or by using TA45 "star" guy brackets 
and double guys at each level)?  I also know that many users have 
significantly overloaded towers when compared to Rohn's catalog 
designs and gotten away with it.  

Is the added cost (about 25%) for Rohn 55 "worthwhile" -- is it 
really that much stronger or is Rohn 45 "as good" when guyed the 
same way as 55?  


   ... Joe, K4IK 


See:  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
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