On 12/31/12 9:21 AM, Larry Loen wrote:
Wow, I've received a bunch of _very_ ingenious answers, but as they were
mostly private, I won't post them.
Still, it suggests some added clarifications:
1. As I live in Arizona, there is a summer 'monsoon' season with serious
lightning potentials. Some colleagues here tend to leave their tower
retracted in the summer when DX is scarce and lightning is more common.
I've seen cloud to ground out here out of clouds that aren't even _raining_
yet. Lots of it, in fact. So, I'm planning on at least some periods of
time with the tower routinely retracted. Lightning strike potential, per
year, is at least as strong here as anywhere else I've lived. It may be
the dessert, but lightning doesn't seem to care.
If lightning hits the retracted tower, and travels down the coax shield
(as it is likely to do), then you might wind up replacing the coax near
where it touches the ground.
This is an interesting take on the usual "bond the shield to the tower
at the top and bottom" advice because the configuration isn't fixed.
3. Because the tilt over will be at least sometimes there and because the
finish on the cement is fairly rough, I don't want to see the coax and
control cable scuffed. Someone suggested I might consider netting to
"catch" the coax on lowering. That is an option to consider.
or cheap sacrificial carpet/astroturf/wood on top of the concrete that
you just replace when it gets too ugly?
the arms. That really would be my preferred solution. Some have suggested
giving up on remote raising/lowering and guiding the coax with some sort of
control ropes (I presume, dacron ropes). That would be another way to deal
with the snagging problem.
Interesting.. you could also do what they do with the control/power
cables for moving bridge cranes and the like.. they have loops and clips
that run along a steel messenger line. Think shower curtain and shower
rod. With a suitable spring loaded retractor, you could have a straight
messenger line along side the tower.
I don't know if that saves anything, but it would mean you could do away
with the standoffs sticking out from all the intermediate sections.
You'd have just one at the top and the "stretchy steel cable" reaching
to the bottom from it. Do the loops and attachment to the cable sliders
right, and you might wind up with an "autocoiled" cable nicely hanging
there. They make a sort of split loop stuff with a spring steel member
that tends to coil in a preferred direction (you see a version of it on
those pneumatic masts on TV trucks, for instance).
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