[UK-CONTEST] Buried coax

Ken Eastty ken.g3lvp at btinternet.com
Sat Mar 20 08:33:11 PDT 2010


>
>
>
> I wonder what your experience is with buried cables, in " ordinary"
> garden environments? That might include e.g. RG213type coax and/or pvc
> sheathed control cables.Have you used conduit and/or have you been
> cavalier and buried directly?
>

The (5) feeders & rotator cable between the house & base of my mast run 
underground in a 5 ft. length of plastic drain pipe (unsealed at both 
ends).
Last year I noticed some odd effects when using the HF beam. I eventualy 
traced the problem to the braid of the RG213 feeding the HF beam being 
completely open circuit. This was caused by the braid being corroded 
over a length of about 10ft by water ingress through a small nick in the 
outer sheath, capillary action had done the rest.
Identifying the fault was made difficult by earths from the other feeders.

I remember an incident many years ago at GKR - Wick Radio where water 
was pouring out of the end of a coax where the outer sheath had been 
damaged, not as bad as on another occasion at GND - Stonehaven Radio 
when a damaged underground cable duct filled with water and flooded a 
building (I'd forgotten how much fun that job was!).

My advice would be to put the feeder in a duct and seal it against water 
ingress. Which reminds me that I still have a little job to do outside...!

73...

Ken

G3LVP


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