On May 25, 2006, at 7:41 AM, Martin & Ann Mein wrote:
> I've decided to mount a snall-diameter tower, 35-40 feet high, side-
> mounted to a building. The building is 15 feet high. What type of
> base should I use for the tower? Do I need a big cement base, or
> anything elaborate? There would be also a bracket at the bottom,
> connected to the building, and also at the top.
Assuming you are using Rohn 25 for this. If you are using something
else, do what that manufacturer says.
Get a Rohn catalog. It has a diagram for the base of a bracketed
tower. The base is 2x2x4 feet. Place 4 feet and a few inches of tower
section into the base (about 2-4" should stick out the bottom and be
placed in a 6" gravel bed to allow the legs of the tower to drain
away any condensation)
With a 15 foot high building and the tower embedded in the base, you
shouldn't need more than one bracket. Put it at 15 feet. Don't use
lag bolts! Use galvanize carriage bolts to mount the bracket to the
building and heavily re-enforce this junction.
I wouldn't go beyond about 20 feet above the bracket. Rohn 25 gets a
bit too wiggly much higher. You can use a long mast for 5-8 more
feet, assuming you're just mounting a small tribander or VHF yagis.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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