[TowerTalk] Blackened Sheild on Belden Coax?

[Guy Olinger, K2AV]

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



----- Original Message -----
From: Mike Foerster <mike.foerster@home.com>
To: TowerTalk <towertalk@contesting.com>
Sent: Monday, September 18, 2000 10:37 PM
Subject: [TowerTalk] Blackened Sheild on Belden Coax?


>
> I just put some connectors on some coax that I "inherited" with the
used
> tower that I'm putting
> up.
>
> It came with 2 chunks of coax, 90' of Belden 8837, RG8U and 100 ft of
> "Tandy" RG8U.
>
> The loss measurement is very low on both, about 1 dB at 28 MHz.
(nominal
> for this coax)
>
> I was surprised to see that the copper shield on the Belden coax had
turned
> very black
> when I stripped it to put the connector on the end that was cut.  I
> suspected some moisture,
> so I cut it back several times, about 2 ft, still just as black.
>
> I ended up scraping the blacken part and put connector on it (wrapped
with
> some very
> fine wire and soldered that to it, then put on the connector).  I'll
use it
> for my 80m dipole,
> but I'm puzzled as to why it would turn black.
>
> I would guess that it's about 6 years old.
>
> Mike
>
>
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>


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