W0UN writes:
>
> As has been mentioned MOST PVC and PVCII cables are
> not designed for direct burial. There can be microscopic
> pin holes in the jacket that can wick in moisture and
> degrade the cable over time. And the problem is that it
> is impossible to detect the degradation from the shack.
> The VSWR tends to get even better with time as the
> cable loss goes up. The only real way to tell if the cable
> has deteriorated is to do a "before and after" watt meter
> test at the far end of the cable to see just what the loss in
> the cable is.
>
> So the answer is to put the cable in a conduit of some sort--
> typically plastic pipe, right? WRONG, wrong, and more wrong.
I sometimes use good quality rubber water hose in order to protect individual
coax lines from underground or underwater elements. Find the right diameter
water hose, slip it over the coax, seal the ends between the coax and hose
with hot melt glue, and/or pack with Vaseline close to ends. If you need
longer run, more pieces of water hose with their own couplings and rubber
washers would do. If it is good for water not to get out of the hose, it is
good (much better) for water not to get in to the precious coax. You can feed
them then through the 4" PVC conduits for future replacements, etc.
This almost eliminates any chance of coax sucking in the moisture, rubber
gives with pressure dropping or raising, so no chance for air excursions
(providing coax ends/connectors are sealed accordingly).
Yuri, K3BU, VE3BMV, VE1BY
List Sponsor: ChampionRadio.com - Trylon self-supporting towers,
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