For what it's worth, I was always a little concerned about the
installation at my parents house when I was a kid. It is 70 feet of
Rohn 45G on a hill with a little 2L 40 at the top of the tower, a 4
element 20 up about 8 feet and a 4 element 15 at about 16 feet above the
top of the tower. The mast is 24 feet of 2 inch OD x .375 wall, 6061-T6
extruded aluminum. I think I would really be concerned if that mast was
.250". It has now been up over 35 years and never a slight hint of a
problem. Two levels of guys and two of the three directions are to
large oak trees. All that still stands to support a star welded out of
rebar that lights up at Christmas time for my mother and everyone in
town who enjoys seeing it. :-)
Stan, K5GO
----- Original Message -----
From: <K7LXC@aol.com>
To: <towertalk@contesting.com>; <k0is@iowatelecom.net>
Sent: Tuesday, May 04, 2010 12:38 PM
Subject: Re: [TowerTalk] 2" OD tubing inside a Rohn 25AG2
>
> 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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