In a message dated 5/2/2010 9:59:22 P.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> Tom, There is no way I would use ANY aluminum tubing as a mast at any
time. In this case there are three
problems.....aluminum....tubing.....length. Tubing is not pipe and that
length of it with any substantial weight,
i.e. windload, is inviting disaster. Another section of tower is the ONLY
correct and safe way to achieve the height you're after. It's cheaper to
do it right once than to do it twice to GET it right. For what it's
worth....I'm no expert. I'd be interested to see what K7LXC has to say about
your question.
Well, like the engineers say - it depends. Of course for an aggressive
installation of stacked big yagis or a moderate installation in a high
wind area you should use a carbon alloy steel tubing mast of appropriate
dimensions and strength. For small to moderate installations many times an
aluminum mast (35 kpsi yield strength) will work fine. Not everyone needs a
chro-moly mast for $600. Heck, if you're just putting up a 3L tribander at the
top of the tower, even water pipe will be okay since there's very little in
the way of bending moment on the mast.
There's a whole chapter on masts in my UP THE TOWER book available
from _www.championradio.com_ (http://www.championradio.com) .
Cheers,
Steve K7LXC
Champion Radio Products
888-833-3104
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