Date: Wed, 11 Jan 2012 07:45:02 -0500 (EST)
Subject: [TowerTalk] Fwd: How to get another 10' in height? Add a mast
or add an...
You only have to climb a tower once to know that you want as little as
possible "complications" once you are "up there". Also, it is not the top of
the tower that is exposed to stress, it's the bottom. The tower section
"below" have to take the mechanical stress from whatever is above. That's the
reason you design the tower from top-down.
Design the tower for the height you need and don't plan to add anything
Hans - N2JFS
// a buddy installed 190 feet of rohn 55 g... with 4 x sets of KX0G rings.
tower rotates. I discovered that Rohn makes these super heavy duty versions
of 45, 55, 65 G.
They are not only Z braced, they are also X braced. He used 3 of the super
heavy duty sections
for the top 3 x sections of the tower. The very top guy ring was at 175 feet.
So he has 25`feet of
unsupported tower above the top ring. A 2-el 80m yagi is at the very top of
the tower. 4-el 40m yagi
below that..and a 5-el 20m yagi below that..all in that 25 foot unsupported
section . Each of the
heavy duty sections costs a bit more..and also weighs a bit more. They are
VERY strong sections.
One helluva lot stronger than a stock 45,55,65 section. We also looked at
using 65G. My problem with
65g was each step is 18 inchs... vs 15 inchs on 45G, and 55G. With
horizontal steps being 18 inchs
apart, that makes climbing tougher to say the least. Once 55G was decided
on, the next step was to
figure out how much unsupported tower can be above the top ring. The 3 x new
guy anchors are out aprx
175`feet. The re-enforced X + Z braced stuff for the top 3 x sections fit
the bill perfectly. So far, so good.
The same tower supports 1 x 80m yagi, 2 x 40m yagi`s.... 3 x 20m yagi`s..
and a single yagi for 17,15,12,10,6m.
So x 11 yagi`s in total.
later.... Jim VE7RF
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