[TowerTalk] Installation Rohn 25G

[Bill Coleman]

On Nov 11, 2007, at 8:06 PM, David Calder wrote:

> The two towers you see. Both are 40' Rohn 25 "not
> guyed".
> 1 has a A3S tribander, a 12 el 2 meter SSB AND a 24 el 440 SSB  
> antenna on
> it.
>
> The other has a 6 Meter beam, stacked 2 meter beams and an omni.
>
> Now, they are tied at 10' with a house bracket on the roof. But they  
> are
> NOT GUYED.

There's a big difference between "not guyed" and free-standing.  
Bracketing is another method of giving a tower vertical support.

You are probably lucky that they are still standing, as 40 feet  
bracketed at 10 feet of Rohn 25 is not rated to withstand 100+ winds  
with the sort of antenna load you have on them. 70 mph would be OK.  
Remember that the wind pressure increases with the square of the  
velocity.

It's amazing the A3S withstood those winds.

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