On 6/13/2011 12:39 PM, K0DAN wrote:
> Seems I saw a post here within the last year that diagnosed the cause of
> blackened copper shield?
> My case: I have a buried run of Cable Experts RG213/U Mil Spec, supposedly
> good for direct burial. It recently got nailed by the lawnmower (thanks to
> the XYL!), but there's enough stub left above ground to repair and add a
> connector, salvaging the buried run.
> I looked at a few of the chopped up pieces and the copper braid is BLACK.
> The center conductor looks normal, slightly dull copper color but in good
> shape, easily cleaned with steel wool for solder/connector.
> I would expect to see some kind of green or brown corrosion, but black? Is
> this maybe silver plate braid and I'm seeing silver oxidation? Web site says
> it's copper, not silver.
IIRC Copper Oxide is black. Sulfide (fertilizers and atmospheric crap
are *usually*green). Water varies depending on what's in it.
Cut the jacket back until the braid is clean and shiny copper. Oxide is
a bear to try and solder. Don't let water get in there. If you can't
fix it right away, seal it thoroughly.
> The cable otherwise looks in decent shape, and I do not believe it burned
> due to high SWR or lightning.
> I don't really want to replace the whole run but don't know the cause or
> extent of the blackened braid. I have doubts I can clean it up and make
> decent electrical connections but am willing to try.
> RF loss is not an issue, any antennas on this line will be below 7 Mhz.
> Tnx es 73
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