In a message dated 96-12-09 19:17:33 EST, you write:
> I have a 130 foot Rohn 25G tower in my yard with a TH7DXX at
>132 feet and a 402CD at 140 feet on the 20 foot mast (7 down, 13 up). In
>the past, it has also held a TIC RotorRing at 68 feet with a Classic 33 on
>it. In addition, it has 3 each 13B2s at the 120 foot level. It is guyed
>with quarter inch Seimens-Marten (sp?) galvanized steel cable that is
>anchored at 3 points, 120 degrees apart, with 4,000 lbs (1 yard) of
>concrete at each anchor point. The guys are at 32, 64, 96, and 128 ft
>on the tower. The tower only has a half yard of concrete at the base.
>The 4,000 lb rated guys (I'm sure they are derated by Seimens-Martin)
>are tensioned to 10% of their ratings - 400 lbs. I defy you to climb it
>and do anything at the top that would make it feel "pretty limber". It
>is as solid as a rock.
Hi, Rod --
You've done everything by the book as far as I can tell. Since Madison
County is only a 70 MPH wind zone, you've got a pretty benign wind
environment to live with.
BTW, Siemens-Martin grade guy wire is approximately 60% as strong as the
factory specified EHS. For example, 3/16 EHS is rated at 3990# whereas the
3/16 Siemens-Martin grade is rated at 2550#. Since you went to the next
bigger size, you've basically gotten the correct strength guy wire. And
congratulations for actually knowing your guy wire tension - you're in the
minority.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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