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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