>Gentlemen:
>Have Rohn 25g tower on ground ready to erect. I have the GA25 Guy
>bracket with TB25 torque bars. The holes which are punched in the ends
>of the torque bars seem to have rather sharp edges and I think will
>chafe the guy cables in time. How does one attach the cable to these
>safely?
>Also, I have a 4' piece of standard 25 tower section which I intend to
>embed in concrete for the base. Any problems with this?
>Can someone tell me which zone I am in for wind loading (60 mi. straight
>north Green Bay, Wi.) Will 3/16 EHS work?
>Any comments would be appreciated.
>Tom Hellem K0SN
>Porterfield, Wi.
>
>
>
>--
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Tom, I have 90' of Rohn 45G up using three sets of 3/16" EHS (at
30/60/90'). This configuration, I figure, puts me somewhere around a 90 MPH
windspeed rating. By all means, use the shackles in the torque bars to
attach the guywires. That's what I did. Shackles, turnbuckles, in fact,
everything you need to complete your tower can be found much cheaper at a
wire-rope and rigging supply shop than from amateur radio stores or
catalog. I used a rigging shop in Spokane, WA who routinely caters to the
professional crane, rigging and logging companies. The only problem he had
was sometimes finding parts *small* enough for my application. I bought a
box of miscellaneous shackles that he had lying in the back and were
covered in oil and dirt for a buck a piece. There were over thirty shackles
in that box, and all of them were in good shape and cleaned up well with a
wire brush. They all were a size or two heavier than what I would have
normally bought, particularly if I had to pay "amateur" prices.
The guys at a professional rigging shop are also a wealth of knowledge and
experience, and will be able to steer you in the right direction if you
have questions about what you need, the proper applications, and the way to
get things done the right way. I did all my guywires with swagged or
press-fit fittings instead of wire clamps or preformed grips (except where
the guywire attached to the anchor rod equalizer plate). They showed me how
to operate the handtool to press the swages, and even pull-tested a sample
of 3/16" EHS with a loop in each end done up with the swage fittings and
thimbles. The swages did NOT fail first! Much faster than cable clamps (and
cheaper) and much less expensive than preformed grips.
Another source of parts in your area, especially if you want copies of Rohn
fittings like equalizer plates, etc, is Marinette Marine (or one of their
workers) if MM is still in business, or one of the small welding and metal
work shops in Marinette/Menominee or Green Bay. There was a small shop in
the industrial area behind the Marinette Mall, as I recall. Take your Rohn
drawings over to one of these shops and get an estimate, then compare it to
the amateur radio prices. Hot dip galvanizing might be expensive, unless
you have enough parts to make it worth your while to pay the per-pound and
set-up fees, then again, they might let you piggy-back in on someone elses
galvanizing run if there is room in the basket. Talk nice. Otherwise, I
have had very good luck with the cold-galvanizing spraypaint that Ace
Hardware sells, followed by a coat of good, rust-resistant enamal. I have
had our local welding shop make up "swinging-side arm" rotator mounts, and
a variety of other parts for me with great success. Just remember, if it is
load-bearing, and/or it's failure could hurt someone or damage property,
don't use a shop or welder that can't/won't show you the "pedigree" of the
materials or break a sample of the welding.
If you have anymore questions, don't hesitate to ask. You came to the right
place -- the Towertalk folks did such a good job helping me with my first
tower, I am currently planning a second (and third, and . . .)
73,
Steve Zettel KJ7CH
near Libby, MT USA
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
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