Greetings Fellow Towertalkians,
I am slowly gathering parts and money for a tower project, that I hope
to install in a year or two. In the meantime, I would like to upgrade my
antennas as my budget allows. I got a pretty good deal on a 9 ft Glen
Martin roof tower and a Force 12 C-4XL.
The house is 2500 Sq. Ft, 1973 two story. There is a 700 Sq. Ft attached
garage too. Typical residential, wood frame construction with roof
rafters on 24” centers. All roofs have soffits of about 12” around the
entire house. I am reinforcing the rafters per the Glen Martin
installation instructions.
I currently have a 3 different roof mounted antennas, a 10M vertical
mounted on a 3 foot tripod, and a 2M/440 application mounted on a tripod
with a vertical and a 2M 14El Yagi on the same mast. In order to make
room for the Force 12’s 23.8 ft turning radius, the 2M/440 set up is
being moved and upgraded to a 4 foot Glen Martin roof tower. As an
aside, while I’m up there sometime this summer, I would like to
reinstall my large, deep fringe area, TV antenna and rotor. My plans
are to install this on another Glen Martin 4 ft. tower, because I could
also attach side arms to it for improving both my cell phone and
internet coverage.
I am concerned about not having enough separation between antennas to
prevent interaction and RF overloading. I thought I had read somewhere
that I need ¼ wavelength separation vertically for antennas on the same
mast. But how far away horizontally from the Force 12 would I need to
mount another antenna(s)? Is there any way to install filters through a
switching network? Not that I’m planning on running a multi operator, 2
radio system, but how do the big contest stations handle this? What does
one do if they don’t have acres of land so their receiving antennas are
far away from the transmitting antennas?
Other questions I have are, what is the best way to route the coax runs
across the roof? Has anyone fabricated or used coax standoff’s and roof
mounted them to manage the coax runs? How did you make them? How did you
attach them? How did you seal them to prevent leaks? Remember the 12”
soffits I mentioned? I have never liked having to go over the 12” rafter
tail of the roof. The run either rubs on a gutter or deflects the
shingles that hang slightly over the drip edge. What is the best way to
route my coax down from the roof? Has anyone used a roof vent to go into
the house directly from the roof? Has anyone ever purchased and
installed a separate electric utility service mast and weather head and
used it as a way to get the coax runs through the roof and soffit and to
the ground and shack? Also, can I route the 4 awg copper ground with the
coax, or should I keep this separate?
Thanks. Kurt
KD8MGN
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