Hi guys, I'm in the process of relocating my 35' freestanding Rohn 25G tower
after 8.5 years on the air. I figured this time I'll bracket it to the
house, which is what I should have done in the first place. But I've run
across a few problems with the Rohn specifications:
1. The tower will be bracketed to the house mid-way up and also near
the top of the tower with an eave bracket. The specifications for the
brackets "must support a minimum horizontal force of 815 pounds". I can't
find any calculations for how they came up with this number. And it seems
very excessive for a modest 35 foot tower bracketed in two places.
2. The specs also state that the base must be a "fixed base", rather
than a pinned base. Again, in this case I don't understand why a pinned base
wouldn't be sufficient for a well-bracketed tower. Why would the base
experience any lateral loading?
3. The specs also state that the base has to be the same 2x2x4 feet of
concrete that was spec'ed for self-supporting and guyed towers. In this case
I can understand somewhat having a solid chunk of concrete for the thing to
rest on, but the entire weight of the tower and antenna will be, by my
calculations just a little over 200 lbs. It doesn't seem to me that it needs
a 2000 lb chunk of concrete to keep that from sinking into the soil.
So in short, I'm just wondering if Rohn is simply CYA'ing themselves, or are
these specs really to be taken literally?
Thanks and 73,
-- Dave WA0TTN
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