> Thanks for the reply Tom. I'm using 7/8" Heliax
> (LDF5-50A). Is it considered acceptable to direct bury
> that coax? I'll probably go with conduit, but direct
> burial might be a reasonable alternative.
Any of the modern Heliax cables I have seen are closed cell
with the dielectric bonded to the center and shield. The
shield is also a solid "pipe", and even if it does leak the
water has nowhere to go.
Not only that, the primary mechanism of loss after moisture
is contamination of the braid. it insulates all the pressure
connections from lay to lay.
I don't give a second thought to burying my "hardline"
cables. I recently measured the loss on a 400 foot plus run
to my 40 meter vertical and with 26-27 watts applied there
was 25 watts at the antenna. That cable has been in the
ground for 8 years, and prior to that laid outside with open
ends for years. Only the first half inch had any signs of
the conductors discoloring.
You can of course get water in a hollow center conductor,
but after you drain it and dry it and install connectors the
cable is fine.
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