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Re: [TowerTalk] Reduced guy radius for Rohn 45G tower

To: "Towertalk reflector" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Reduced guy radius for Rohn 45G tower
From: "Dave Hachadorian" <k6ll@arrl.net>
Reply-to: Dave Hachadorian <k6ll@arrl.net>
Date: Thu, 23 Aug 2012 13:55:04 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Rohn used to make a 45G foldover tower, and had a 4-way guying 
scheme that had a small footprint.  I think they made them up to 
65 feet, and quoted windload specs.  Maybe someone here has those 
old catalogs.

Also, Rohn 45 is capable of use hundreds of feet high, so the 
inline compression at 65 feet is way below what the tower is 
capable of.  The guying footprint could be reduced substantially, 
as long as you use heavy enough guy cable, and suitable anchors. 
This would require an engineered solution, which shouldn't be too 
expensive, if you choose the right engineer.  KR7X would be a 
good starting point.


Dave Hachadorian, K6LL
Big Bear Lake, California






-----Original Message----- 
From: Avery Davis
Sent: Wednesday, August 22, 2012 10:33 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Reduced guy radius for Rohn 45G tower

Pardon me if this is a dumb question for my first post to this 
list, but
this is my first real tower after many years in Amateur Radio.

I came across a great deal on a lightly used Rohn 45G:  six 
sections
plus a top section.  The problem is that my lot is not really big 
enough
for the 56 foot guy anchor radius recommended in the Rohn 
brochure.  I
am looking for suggestions as to what I can do to make this 
smaller.
For example, I could put up just a few of these sections with no 
guys.
The Rohn 45G self-supporting tower brochure has a table for 90MPH 
(which
I understand is required for my jurisdiction, although radial ice 
is
not), but this only allows 30 feet height with 4 sq.ft.  This is 
smaller
than I would prefer, which is nominally about 10 sq.ft., but the 
Rohn
brochure puts me at only 20 ft. height for 11 sq. ft.  So, what 
can I do
with these tower sections to get more than 30' height and 10 
sq.ft. in a
radius less than about 20 ft.?  Would it help to use three 
sections as
elevated guy anchors?  This would leave me three sections plus 
the top
for 3x10 + 8 - 4 = 34'.  How do I determine the wind load 
allowance for
this configuration?

Or, would you recommend I just resell the 45G and buy a genuine
self-supporting tower?

73,
Avery, WB4RTP

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