[TowerTalk] Bracketed 45G

K7LXC at aol.com K7LXC at aol.com
Thu Jun 15 12:20:57 EDT 2006

In a message dated 6/14/2006 3:50:27 P.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  I am working on plans for a 50' bracketed Rohn 45 tower. In  going through 
the Rohn catalog looking at foundation drawings for Rohn 45  bracketed 
towers, you can either use a base plate or plant a tower section  in concrete 
for the foundation. Is there a reason not to use one method or  the other? 
This tower needs to be unguyed and will be bracketed to a brick  building for 
a community installation. The county wind rating is 75MPH.  The antenna load 
will be less than 8 sq feet. The top bracket will need to  be a little lower 
than the Rohn specs. 45G was selected over 25G because  of this. Any 
recommendations or caveats are  appreciated.

        My first question is what  heights it's going to be housebracketed at 
and how much tower will be  above the top bracket (Rohn specs call for 2 
brackets)? The Rohn specs allow 14  feet above the top bracket and will take 
approximately 30 square feet at 75 MPH.  (Obviously you can go up a little higher 
while de-rating the capacity.)
        In my experience, having  the bottom of the tower in the concrete is 
much more stable than bolting a  baseplate to the concrete but since the 
brackets will be taking the side forces,  it doesn't make much difference which way 
you go. 
Steve    K7LXC
Professional tower services for hams
Cell: 206-890-4188

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