FW: [TowerTalk] Blackened Shield on Belden Coax?

[Paul Finch]

Hello List,

After several years in the commercial Two-Way and Paging industry I have
seen this in almost all RG type coax cables.  I have even seen it in the
more expensive double-shield-silver plated RG-214 type coax.  I don't know
what causes it or what it is but it makes it really difficult to solder old
coax. I feel it has to be some kind of tarnish reaction to tinned copper,
copper or silver plating.

Question, what causes tarnish on copper and silver?  Could this be corrected
by Tarn-X as seen on TV, at least to get it to solder. Just a thought.

I also concur with the previous post that the blackened shield does not
cause performance problems with the coax.  I have several now with this
problem and no notable degradation, just a problem to solder to.
Paul
WB5IDM


-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of Guy Olinger, K2AV
Sent: Monday, September 18, 2000 10:16 PM
To: Mike Foerster; TowerTalk
Subject: Re: [TowerTalk] Blackened Sheild on Belden Coax?



I have done that to coax by operating high power at a relatively high
swr. I presume the blackened spots were the current maxima, and got hot
enough to interact with the covering.

- - . . .   . . . - -     .   . . .     - - .   . - . .

73, Guy
k2av@contesting.com
Apex, NC, USA





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