FWIW, we've always had one of those invisible dog fences. The antenna system
for those is basically a loop of insulated #14 AWG wire shoved into a slit in
the lawn cut with an edger.
Early in their lifecycle they are prone to damage from the lawn mower when
frost heaves or whatever expose a section. That wire is always black under the
insulation after only a year of burial and is a bitch to get clean enough to
solder.
Al
AB2ZY
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of K0DAN
Sent: Monday, June 13, 2011 8:01 PM
To: K8RI on TT
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] BLACKENED BRAID?
Thanks...will see what we have. I have a vision of peeling the braid all the
way back to the hamshack! Could be this "direct burial" stuff really wasn't,
and the jacket allowed moisture to get into the shield.
73
k0dan
----- Original Message -----
From: "K8RI on TT" <k8ri-on-towertalk@tm.net>
To: <towertalk@contesting.com>
Sent: Monday, June 13, 2011 11:56 AM
Subject: Re: [TowerTalk] BLACKENED BRAID?
> 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.
>
> 73
>
> Roger (K8RI)
>> 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.
>>
>> Ideas?
>>
>> Tnx es 73
>>
>> Dan
>> K0DAN
>>
>>
>>
>> _______________________________________________
>>
>>
>>
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>
>
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