Hello Jim,
I've had a 55 foot crank up in service for 30 some years. I have a rotor loop
at the top of the tower, and from that point the cables simply drop though
guides to the ground. Originally the tower was equipped with assemblies that
bolted to the top of each section, and the cables were solidly attached to each
of these assemblies. That meant you had to have the exactly length of cable
between sections. I replaced the original hardware with U-bolts. The cables
attach at the top of the top section and then pass through guides like guides
on a fishing rod on the other two sections. The cables just drop through down
to ground level.
Like you, I keep it down between contests or DXpeditions and out of the weather.
73 Steve K0SR
-----Original Message-----
From: Jim George [mailto:n3bb@mindspring.com]
Sent: Sunday, December 25, 2016 02:04 PM
To: cq-contest@contesting.com
Subject: [CQ-Contest] Question regarding crank-up tower feedlines
I've had a three-section crank-up tower (it used to be called the LM-354)
that's 54 feet tall when fully extended. For a long time, I used it in a
permanent fully-extended manner, with phased ten meter yagis at the top and
half-way up. Now, it will have a triband yagi and a two-element 40 yagi on it,
above the thrust bearing, and I wish to keep it at least semi-nested between
contests to avoid storm damage. What is the recommended way of bringing down
two the coax feedlines and the rotator cable for a tower that will go up and
down fairly regularly? I'm going to use the three original "stand-offs" to keep
the coax and the rotator cable hanging vertically as these three standoffs are
positioned such that they nest properly when the tower is down. Is it okay
simply to hang the feedlines and the rotator cable down through the top
standoff, which seems to rotate around as the rotator moves the mast, and
simply let the coax and cable drop down vertically? In this case, there would
be no traditional rotator loop. That configuration has worked okayrecently
with only the small 40 meter yagi on the top.Another possibility would be to
form a five or ten foot "rotator loop" with the feedlines and rotator cable and
then route them back up onto the top standoff and down vertically through the
other two. In this way, the system would not require that top standoff to move
around on its tower leg as the mast and antennas rotate. Not sure if I
described this in a clear way. If I were sure that the top standoff would move
around on its tower leg, that would work, but if the top standoff got stuck and
didn't move, then the feedlines and rotator cable could get stretched and
damaged. For some reason, I haven't seen anything on this, or have forgotten.
Any recommendations?Thanks in advance, and all the best at the Christmas and
other holiday breaks and new year.73, Jim George
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