Hi All,
I am planning a new EME array that will overload my 2 1/2" mast. This mast
is fastened to the
attic floor, 4 feet below the roof. It is obvious that I need to either
strengthen the mast or add
guy wires. I will need to hold something on the order of 15 sq ft of
windload at a height of
10 feet above the roof. This works out to something like 5000 lbs at the
base of the mast
even though only something much less then 600 lbs of lateral force will be
applied to the mast
at 10 feet above the roof. Guy wires seem to be the logical solution even if
they are to be steep
so as not to interfere with the array. I am thinking about something like 3
feet out in four directions.
I am thinking that 3/16" Rohn guy wire should handle this with its 4000 lb
rating and add substantially
to the strength of the mast. The guys would be attached about 6 feet up.
Above this there is a rotating
mast.
Long way to a short question;
Given that there can be a lot of force in line with these guy wires, what
is the preferred method
for attachment to the roof to ensure that the roof does not leak? It seems
that some flexible
gasket is needed for water proofing? The mast is fed through the roof with a
standard vent gasket
and does not leak. If I added eye bolts to the roof for guying and it
started leaking, I would be in
hot water with the XYL!
A second question.
Is there a known hazer type solution for a mast pipe?
Perhaps something that would allow 10 feet at full height and nest
to 5 feet for working on the array?
73, Jim Shaffer, WB9UWA.
2M EME 205 initials.
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