On 10/13/2014 2:23 PM, Ian Jackson wrote:
In message ,
Lostgallifreyan writes
Jerry Stuckle wrote in news:m1gvg0$9v8$1@dont-
email.me:

One side note. Copper clad anything is not certified for any ethernet
cables. Even though ethernet runs at very high frequencies, only solid
or stranded copper is acceptable.


Telewest, who became Blueyonder, then after merging with ATL got
bought by
Vitgin Media here in Britain, used copper clad steel cores. I don't know
enough to comment on their reasons, but it's definitely true, I just
waved a
magnet at a few cables of theirs to prove it. My guess is that because
the
lines were ostensibly for cable TV, they just coerced them into internet
wiring later. ADSL on the phone lines later beat them for speed,
presumably
because the phones were using solid copper, but I'm not sure they used
in the
external cables because I can't reach one right now.

Are you confusing the internet being carried (like cable TV) over coax
at RF, and via ADSL on twisted-pair phone lines? The coax drop cables
are usually RG6, which has a copper-plated steel inner.


The cheaper RG6 has copper clad steel. The stuff we use is
quad-shielded with a solid copper core.

If it's anything like some coax I worked with in the 60s, there might be
a small 'kink' in the frequency response* at around 40MHz, which is
probably the frequency at which all the RF has moved out of the steel
core, and into the copper plating.
*Above 40MHz, the attenuation might become somewhat lower than you would
expect from extrapolating loss figures obtained below 40MHz. While I
have to say that I've never noticed this with RG6, this may be because
I've never looked for it. In any case, it often has been in the
guardband where the crossover between the cable TV forward and reverse
RF paths occur.

I never tested it, but I think the skin effect would move the rf out of
the core at a lower frequency. Perhaps some ferromagnetic effect with
the steel?

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Jerry, AI0K

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