[UK-CONTEST] ] Buried coax

[ALEX LISTER]

If using Duct
Don,t forget the mouse bait for the rodents.
Incidentally I am using some large diameter 50 ohm Yellow ethernet,
With a solid dielectric for a long run to HF vertical , Been in ground some time 
Sleeved with Plastic conduit . Seems OK.

If ur going to do job properly and have a non solid dialecric. 
Then Squirt some dried clean air up it.
Or for EME RX some gas !
But you will need to find a friendly cable contractor for the air bits !
Alex Lister
G8FCQ
Member Leicester Radio Society G3LRS/G2AA
Member DMUARS
0753 120 1640

--- @ WiseStamp Signature. Get it now




________________________________
From: Ken Eastty <ken.g3lvp at btinternet.com>
To: uk-contest at contesting.com
Sent: Saturday, 20 March, 2010 15:33:11
Subject: Re: [UK-CONTEST] Buried coax


>
>
>
> 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
_______________________________________________
UK-Contest mailing list
UK-Contest at contesting.com
http://lists.contesting.com/mailman/listinfo/uk-contest