[TowerTalk] BLACKENED BRAID?

[Al Kozakiewicz]

Maybe it's the soil ph or something...

I've taken to using black PVC water pipe.  It's cheap and is almost as easily buried as coax.  I jump on a flat bladed shovel to sink it full depth; yank the shovel back to expose a crevass; shove the PVC pie in place and drive the 4x4 over the top to relevel the grass.  In a few months the damage has disappeared.

That way replacing the coax is easy if it's ever needed.

Al
AB2ZY

-----Original Message-----
From: K0DAN [mailto:k0dan at comcast.net] 
Sent: Monday, June 13, 2011 8:38 PM
To: Al Kozakiewicz
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] BLACKENED BRAID?

Hmmm...interesting. We too have the invisible dog fence, and I have something like 100' of 14 or 16 gauge insulated household wiring as the buried loop. Have not had any occasions to dig it up or splice, but what you describe is what I see on the shield of my sliced RG213/U. Interestingly, the center strand (twisted) is OK but the shield is gnarly.

As suggested by others I'm gonna pull it back til I find clean copper, but I have a feeling the whole run is gonna have to be replaced.

So much for "Mil Spec" and "direct burial". Caveat Emptor.

73

Dan
K0DAN


----- Original Message -----
From: "Al Kozakiewicz" <akozak at hourglass.com>
To: "'K0DAN'" <k0dan at comcast.net>; "K8RI on TT" <k8ri-on-towertalk at tm.net>
Cc: <towertalk at contesting.com>
Sent: Monday, June 13, 2011 7:27 PM
Subject: RE: [TowerTalk] BLACKENED BRAID?


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 at contesting.com 
[mailto:towertalk-bounces at contesting.com] On Behalf Of K0DAN
Sent: Monday, June 13, 2011 8:01 PM
To: K8RI on TT
Cc: towertalk at 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 at tm.net>
To: <towertalk at 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
>>
>>
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk