In a message dated 97-06-23 15:40:01 EDT, k2kv@netusa.net (Jeff Singer)
writes:
> > I am considering putting up a Glen Martin 17.5 foot roof tower on top of
> > the house and would like your comments. The antenna will be Force 12
> > (either a C3S or C4SXL). I would like to use a 15 foot mast to get the
> > total height up to about 50 feet. At this time, I can't put up a tower
> > so this seems to be the only set up that would work.
> >
> > Any thoughts? Martin says the tower does not have to be guyed but I'm
> > not sure bolting it to the roof would hold the weight. I can't
> > crossbrace the legs because I do not have access to the atic space.
> >
Roof mounted towers can be an effective and relatively cheap antenna
support. The preferred installation method is to put some backing plates
under rafters. In the absence of those, the GME towers can be lag bolted
directly to the roof trusses. If they are spaced correctly for the tower legs
AND you can find them successfully, use as big a lag screw that you can
(probably 3/8 inch by 4-5 inches). Be sure every hole is filled with roofing
tar or something else to keep the water out.
I'd probably opt for the 9 footer rather than the bigger version; it's
got less overturning moment in a big wind and I don't know how far I'd trust
the lag screwed legs with something that big. I could be wrong.
73 and GL, Steve K7LXC
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