Either I am very lucky or the MOVs and GDTs kept my control lines from being
damaged during lightning strikes. I have never had a damaged coax, rotator
or relay cable.
For the feedlines I use Andrew ground kits.
John KK9A
kq2m wrote:
Pete,
Water inside of any cable is an issue - at a minimum it means that the
there exists the possibility of a hole or holes in the outer jacket of
the cable. Has your tower been hit by lightning? A lightning strike
can easily cause heating of the cable which can cause the cable itself
to swell or burst the insulation on the individual wires within the
cable opening it up to shorts, especially as water gets in.
I've had lightning hits here in CT that have caused this problem, with
the rotator control box indicator acting "flakier" and more erratic with
time until it stopped indicating. I eventually replaced the rotator
cable, pulled the old cable off the tower, did a necropysy on it and
found areas of almost microscopic holes in the outside jacket of the
cable leading to water ingress which then allowed water to get into the
strands of the conductors as there were tiny but visible bulges in the
white insulation around the wires where there were barely visible holes.
All of this no doubt from the multiple lightning strikes.
The rotator still worked for months afterwards until the problem grew so
vexing that I swapped out my rotator and took the rotator cable down and
ran a new one. End of problem.
I would be more concerned with any water inside the cable when it gets
cold enough to freeze, because water freezing expands in size as it
becomes ice - so the expansion in volume of the ice will most likely
enlarge any holes/breaks in the cable that you might have. It might
also break individual strands within the wires. Not a situation you
want.
The problem with lightning strikes is that often you can't see where the
holes/breaks might be on the outside of the cable. And then you can't
see any holes/breaks on the inside of the cable because of the outer
jacket. So you may or many not have a problem. But if you do see
bulges or holes/breaks in the cable, then you should replace it.
Otherwise you just postpone the inevitable as the cable will eventually
fail.
73 and GL!
Bob, KQ2M
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