I want to thank everyone for their comments and suggestions, both on and off
list. It was all very helpful.
To summarize... It appears there are two approaches - coil the coax flat on
the top plate like a watch spring, or coil the coax vertically around the
mast like a remote TV truck mast. The flat coil takes a top plate large
enough to accommodate the coil or some kind of support can be added. The
vertical mast coil takes 2-3 feet of clear mast just above the top of the
tower. In any case, make sure there is enough coil and clearance at limits
of rotation.
In my case, I have 2 feet of mast clear just above the top plate and will go
with the remote TV Truck mast coil approach. I built a mock-up of the top
of my tower so I could check out the fit on the ground. At center travel,
there are 4 turns of coax bundle with a diameter of about 9 inches. At 270
deg CW rotation, the bundle diameter is just under 8 inches, and at 270 deg
CCW the bundle diameter expands out to just over 10 inches. This keeps the
coil inside the tower corner bolts and above the thrust bearing hardware. I
have barrel connectors and grounding mounts both on the mast and 3 ft down
the tower so I can replace the coax loops as necessary.
Pics of my mock-up are at
http://s171.photobucket.com/albums/u291/gathorne/Rotor%20Loop/
Thanks again!
73, Glenn/KD0Q
----- Original Message -----
From: "KD0Q-Glenn" <kd0q@traer.net>
To: <towertalk@contesting.com>
Sent: Tuesday, October 09, 2012 3:07 PM
Subject: [TowerTalk] Rotor Loop
I'm getting ready to build coax jumpers for the rotor loop on my tower
using the "2-3 turns around the mast" method. It will be a bumndle of 4
coax feedlines using Davis Bury-FLEX. Does anybody who used this method
have pictures? Any hints from experience?
Thanks,
Glenn/KD0Q
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