Bob,
The Rohn catalog/handbook detail for a bracketed antenna
doesn't tell the whole story.
At my old place in VT, I had 50' of 45G house bracketed,
with a T8 log periodic and an R7000 vertical on top. The system
was bracketed into the roof truss system of a flat-roof house,
as well as the floor-truss system. i.e. two brackets, one at
6', the other at 16'.
Both truss systems were made of 2x12's, due to snow-load
considerations. The lateral load capability of the system,
per architect's calculations, was 3x what the tower was
capable of imposing, with the highest winds ever recorded
in the area.
That said, you need to know what the house will stand, before
you apply a point-load on it. Or, you need to plan for
a structural distribution of the load, within the roof system.
In my case, I had no more than 10sf on top, including the 10'
mast. Dave, K4JRB's point about the th11 is a good one. I wouldn't
be comfortable with it above 40', unless I had numbers to base that
decision upon. One set of guys will make a huge difference.
N2EA
Jim Jarvis, President
The Morse Group, LLC
We create high-performance organizations.
732 548 5573 office
443 618 5560 cell
jimjarvis@themorsegroup.net
www.themorsegroup.net
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