[TowerTalk] Rohn Self Support Chart Says.......

[Bill Coleman]

On May 12, 2006, at 11:56 PM, K8RI on Tower talk wrote:

> My 1990 catalog states "Guyed ROHN towers are not self supporting  
> at any
> height".
> OTOH it seems like I have an older catalog that gives information  
> for self
> supporting installations. Unfortunately I haven't been able to find  
> it.

My catalog (from 2000, I think), clearly states "As a guyed  
structure, [Rohn] 25G can rise to a maximum height of 190 feet. Self- 
supporting and bracketed heights depend on loading are also specified  
in the catalog."

Indeed, the first specification page 25G-1 is the Self-supporting  
Towers table. It lists Rohn 25G has carrying 1.5 square feet of  
antenna at 40 feet in 70 mph winds. This spec is from September 24 of  
1987.

The second specification is a drawing of the self-supporting base --  
which requires a 4x4x4 foot block of concrete, with the tower section  
embedded. This base is four times the size of the bracketed or guyed  
tower base of 2x2x4 feet.

So, far from being "not self supporting at any height", 25G is  
certainly self-supporting when properly installed under very limited  
conditions.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901