Ron,
I'm putting up towers conservatively (lotsa concrete, far guying) and
basically ignoring Rohns specs. I think most are ignoring Rohn's spec - they
are conservative.
Towers do come down around here, but almost always when a tree hits them or
the guys,
73
Ted, KR1G
PS: also remember that a C4-XL, for example, at the top is not the same as
one half the height.
>From: "Ron Bolton" <wu4g@pipeline.com>
>To: <towertalk@contesting.com>
>Subject: [TowerTalk] Rohn and Stacks
To: <towertalk@contesting.com>
>Date: Sun, 7 Oct 2001 20:41:10 -0400
>
>
>Unless I'm missing something here, I'm confused. I see the ads for
>stacking
>controller boxes, rotating tower bearings, rotating rings and such for
>mounting multiple beams on a single tower. The rings systems and the
>rotation tower systems all make models for 45G and 55G. As I have some
>interest in going that direction I decided to spec out some components and
>then figure up costs to see if I could make my dream a reality. What I
>found in the process is that the specs don't add up. I started with the
>current Rohn catalog specs for both 45G and 55G. As I'm in a 75MPH rated
>location, I used the 90MPH figures for 55G. For a 100' tower, it's only
>rated for 16.0 sq. ft. which means stacking just two C-4XL's exceed the
>limits. So from what I see, unless you're lucky enough to live in an area
>where you can use the 70MPH ratings, if you want to stack, you're limited
>to
>something like a TA33. So what's going on with all these pictures I see of
>these nice stack installations? Is everyone ignoring the manufacturer's
>specs? Can't believe the solution is to add more guys to increase the
>ratings as then you can't fit the lower antennas it and rotate them,
>besides, there are no specs from Rohn on how adding more guys affects the
>ratings without using their design service. Is something else besides 55G
>being used? If so, what (and is reasonably priced)? How can the ring
>systems and rotating tower systems honestly market products for 45G/55G
>when
>the towers aren't rated for that type of installation in the first place?
>And finally, if I'd like to stack 2 or 3 decent multibanders (like a
>C-4XL),
>what do you use for tower?
>Thanks.
>
>
>
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