Tom, wouldn't that make 20' sections of 4" irrigation pipe the material of
choice for large (over 40') verticals? Only problem is, I have no idea what
grade of aluminum they are made of.
73, Jerry
----- Original Message -----
From: <n4kg@juno.com>
To: <TOWERTALK@contesting.com>; <Dinsterdog@aol.com>
Sent: Thursday, August 30, 2001 1:06 AM
Subject: [TowerTalk] Vertical Antenna Tubing Strength (was:
Increasingeffective 4SQR array bandwidth???
>
> Yep, NN4T had problems with 2 inch o.d. tapered to 1-1/4 and
> he didn't even have to consider ICE. His 2 inch o.d. 42 ft verticals
> with couplers seem quite rigid with only one set of guys.
>
> Remember, maximum bending moment of a thin cylinder
> goes up as the 4th power of the diameter so a 2 inch diameter
> section will be 16 times stronger than a 1 inch diameter section.
> A double walled section will be less than twice as strong as
> a single walled section of equal wall thickness.
>
> Tom N4KG
>
> On Wed, 29 Aug 2001 23:41:55 EDT Dinsterdog@aol.com writes:
> > 2 1/8 inch to start, originally in 6 foot sections tappered 1/8 inch
> > with a
> > total of nine pieces double walled in joint areas about 6 inches on
> > the first
> > verticals....they been rebuilt so many times now not one is alike
> > the other-
> > 73 Paul N0AH
>
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