We've always built our own, or rather had the welder do it. Steel tubing,
wall thickness determined by loading, weld an H and put the mast in the
middle of the cross bar. Lots of good outdoor enamel, and 4 or 8 unopened
sacks of ready mix for weights. It conforms to the tubing and roof surface,
and won't slide off like cinder blocks have been known to do. After a few
months in the weather they are solid blocks with just the right shape. Some
of our masts are 20 feet tall, but those are guyed to the tips of the "H".

--
Crazy George
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"Bill Blum" wrote in message
m...
Hi there--

We've been given permission to mount a few antennas on the roof of one
of the buildings at school, with the only caveat being "don't make holes
in the roof."

We're looking at some yagis ( LPDA, about 12 feet long ) for VHF work,
and just need to get the things about 10-20 feet above the roof if
possible.

Does anybody have any recommendations/tips on how to handle this? At
work, I've seen large steel mast mounts than lay flat on a roof to
support lightweight/low crosssection antennas... (yes, they're weighted
down with concrete blocks.) Where would I find such a beast? Our
facility manager has NO idea when these mast mounts wound up on the roof
at work.



Thanks.
-bill

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