On Fri, 18 Feb 2005 17:08:59 -0500, Mike Perryman wrote
> Jeff,
>
> I too, have had issues in the past with Cablewave products. Specifiaclly
> when buried, or run up a tower exposed to the elements. I build AM
> directional facilities. No matter what lengths you go to to keep a buried
> line "dry" (mine are usually buried in a piece of sched. 40 PVC pipe)
> water entered through the outer conductor. On a tower a rigger
> sometimes nicks a jacket while working.... water then gets between
> the jacket and outer conductor. With Cablewave it always caused problems.
I can't say I've had many problems with Cablewave foam-dielectric cables in
the situations you describe (either on a tower or buried). I've had
problems with factory-made jumpers, and in all cases, the problem turned out
to be that there was a cold solder joint on the center pin or, in the case
of the solder-less types, that the residual adhesive/film on the center
conductor was not adequately removed (i.e. poor contact).
I have first-hand experience with failure of Cablewave air-dielectric
cables. The most recent was a run of 3 1/8". The internal spacers
collapsed along a segment of cable where it made a gentle bend (several
times greater than Cablewave's minimum bend radius), resulting in the center
conductor migrating toward the shield and arcing over at 29 kW TPO.
If it's my money, I always buy Andrew.
> Seems the Cablewave method of edge welding the outer conductor was never
> 100% water-tight. Any nick in the outer jacket usually resulted in water
> getting into the foam. It has gotten better of the years. But my
> money is on the Andrew product, no water yet... and I always
> install my own connectors.
Eventually it seems water always finds some way of getting into the jacket
of Heliax. The real issue is where the water goes after that. Water
trapped between the jacket and outer conductor is harmless. Water that is
trapped between the jacket and outer conductor that has gravity forcing it
into the connector at the bottom end is another story.
> An old engineer once told me if you need it done correctly the first
> time, you better do it yourself. Then you only have yourself to
> blame if there are problems.
If you're the engineer and it fails, somehow it ends up being your fault
whether it's your mistake or the factory's...
--- Jeff
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