On 6/13/2011 8:01 PM, K0DAN wrote:
> 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.
It all depends on if the deterioration is due to the lawn mower cut, or
was there before the lawn mower got at it. A check with an analyzer
showing loss might be worthwhile.
There are two types of direct burial coax, or more correctly there is
"direct burial" coax and coax that can be buried due to a very rugged
jacket.
True direct burial AFAIK has an insulating, water proof "goo" filling
all the void between the jacket and dielectric. Typically it's
justifiably expensive. The only inexpensive stuff I've seen was
"flooded' RG-6 advertised for direct burial. I use it exclusively for
TV/satellite/cable/internet connections with compression fittings. Get
a nick in the jacket and nothing much happens. Even with a hole the
water can not migrate. There there are very rugged cables like Davis
BuryFlex. it's quite flexible and has a very strong/rugged jacket that
is unlikely to be punctured by stones in soil heaving due to frost. That
jacket is *tough*!
I use it for rotator loops and feed lines to the sloping dipoles AND
wind my RF chokes/current baluns using the *stuff*
73
Roger (K8RI)
>
> 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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