[RFI] Advice - CAT direct burial cable

[Jim Brown]

On Mon,2/29/2016 1:27 PM, Gary Smith wrote:
> Now that my health is a bit better I am going to replace the CAT-5
> cable I have been using for
>
> 1. A 350' run to my remote coax switch.
>
> 2. a 400' run to my HI-Z controller.

How much current, what frequency (or DC), how much IR drop can you 
tolerate for each?  CAT5 is pretty small conductors
.
> What I originally did 5 years ago was buy ribbon CAT-5, used for
> indoor installations and lay it on the ground to the remote Coax box
> and to the HI-Z. Leaves covered it and after a couple of years you
> can't see it.

Belden makes some excellent jacketed CAT5/6 cables. They are strongly 
recommended.

> I am though having issues with RFI I haven't located yet and was
> thinking the parallel wires and not being burial wire may have some
> disadvantage under twisted pair, direct burial cable.

For RFI, twisted pair is VERY superior to parallel wires, but ONLY if 
you're using one pair per circuit.

> Most all of the CAT cable that's direct burial and with twisted pairs
> that I've looked at though use 24G copper clad aluminium wire.

I would reject this sort of cable on the basis of conductor resistance, 
assuming that the control signal is DC or LF AC.  I've had several runs 
of ordinary indoor PVC jacketed cable laying outdoors on the ground for 
about 7 years, with no issues.

Most issues with RFI on long cable runs are likely to be common mode 
rather than differential mode. If that's true, common mode chokes are 
usually the best solution.

73, Jim K9YC