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Re: [TowerTalk] Rohn 55 vs. Rohn 45

To: "Joe Subich, K4IK" <k4ik@subich.com>,"'\"TowerTalk\"'" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Rohn 55 vs. Rohn 45
From: "K8RI on Tower Talk" <k8ri-tower@charter.net>
Date: Thu, 13 Jan 2005 16:27:06 -0500
List-post: <mailto:towertalk@contesting.com>
Don't forget there are ROHN 45s and there are ROHN 45s, then there are 55s and there are 55s. IE, not all 45s or 55s are created equal. Both are, or at least were available in hollow and solid leg forms with a fair difference in ratings.


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.

Look at the difference in seight per section.



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

What do you mean by side rails? Legs?
If you mean legs, then even a 1/16" of an inch makes a substantial difference.


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.

I don't think any of us are going to agree if it's not in the book.

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?

Again, what is the difference in weight? The 55 is supposedly stronger by a good margin.



Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
www.rogerhalstead.com
73,

... Joe, K4IK


_______________________________________________


See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

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_______________________________________________

See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

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