On 2018-11-11 8:44 AM, N4ZR wrote:
> I've never understood typical ham practice of a hanging loop.
Two or three turns laying on the top plate works where one has a
top plate, the turns are supported so they can't shift and catch
on a "corner" of the plate, and there is no snow or ice to freeze
the loops.
Where one has no top plate (a "pointy top" tower, or mast mounted
rotator) or there is snow/ice, the chance of tearing the cables
(or cutting the jacket) is much higher in the "two or three turn"
approach.
In broadcast we do it all the time with Heliax on live trucks.
In every live truck I ever built (several hundred), the *entire*
feedline up the mast was part of the "rotator loop" - that was a
dozen or more three to four foot diameter turns all the way down
a 40 to 60 foot mast. It also resulted in the feedline being
almost twice as long as would have been needed to if it went
straight up the side of the mast.
73,
... Joe, W4TV
On 2018-11-11 8:44 AM, N4ZR wrote:
I've never understood typical ham practice of a hanging loop. What
Chuck describes is mechanically much superior.
73, Pete N4ZR
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On 11/11/2018 8:24 AM, Chuck Tifft via TowerTalk wrote:
No need to transition. I just use about 2 to 3 turns of the LMR in
about a 12" diameter coil basically laying on the top of the tower.
That leaves plenty to absorb 360 degrees of rotation. In broadcast we
do it all the time with Heliax on live trucks.
Chuck W6RD
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