I have watched this thread with interest. I have a 80 Meter 4-Square that went
through many tries before we arrived at the present configuration which has been
standing now for about 3 years.
Our final design is 2" aluminum electrical conduit the first 50 feet. The final
16 feet is 1.5" surplus military mast much like that which is sold by Fair radio
and others I think they are AB-144 Mast kits. The verticals are guyed three
times four ropes at each guy point.
N6BV wanted me to write our experiences but I was too embarrassed to go through
all our blunders. Sometimes the verticals were up for only three days.
Fortunately it was through a contest weekend and we got a taste of how well the
system worked. We were determined to make it work.
We did try 4" irrigation pipe but the diameter did not overcome the weakness of
the thin wall. After more than 2 years of trying different designs we ended up
where we are now. Great bandwidth with 2" pipe.
By the way, I am collecting Rohn 25 sections for the next time I need to put one
of these back up!
We are planning a 4 Square for 40 Meters and 33 feet is going to be a breeze
after struggling with these 66 foot sticks!
Dick - KB1H
"Home of the Barnstormer's Contest Group" - NZ1U
n4kg@juno.com wrote:
> 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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