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OT: Shielded Twisted Pair

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Kevin Bowling

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Nov 11, 2012, 5:05:55 AM11/11/12
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OT but I know the ham radio and comms folks here might enlighten me.

I'm looking to wire up my place with CAT 6A cabling for future 10Gbit
goodness. I'm leaning toward shielded (well, actually "foiled") cable
because at the CAT 6A level UTP gets quite thick in diameter vs. FTP and
looks to be about the same difficulty to install with the vendor I'm
eyeballing.

Now to pose a scenario: if I use FTP, I can guarantee one end at the
patch panel will have a solid ground connection. The far end jack will
most likely not have a local ground, and it's possible that unshielded
patch cables might be used.

I seem to remember that the shield can effectively become a big antenna
if not done properly. Would the above risk that problem?

Regards,


--
Kevin Bowling
Free Comp.* Usenet access at http://csiph.com/

Moussa

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Nov 11, 2012, 9:48:11 AM11/11/12
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Hi Kevin

"Kevin Bowling" <kevin....@kev009.com> wrote in message
news:k7miuv$8cn$1...@csiph.com...
that should be the least of your problems, not sure what are you trying to
achieve by using STP, but remember once you shield, it should be all the
way, that include patch cables, switches, plugs, and pc, etc...., they need
to be all at the same earth potential.

- you need to remember earth become hazardous in nature if is not used
properly.
- you will need a separate earth bar for communications only terminated at
the meter box, by a licensed electrician.
- and don't even think about sharing a STP between buildings, not that it
would not works, it become lethal and hazardous in nature including fire.
- the twist in the cable is more than enough to suppress interference, but
if you run into trouble, you can always use ferrite beads.

my advice unless you have a specific need to use STP, you should avoid it.


Moussa

Moussa

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Nov 11, 2012, 1:20:38 PM11/11/12
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Message has been deleted

Kevin Bowling

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Nov 12, 2012, 4:14:16 AM11/12/12
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On 11/11/2012 12:35 PM, gfre...@aol.com wrote:
> You should not be bonding with the shield in a data cable. In fact
> that is why you only connect the shield at the source end.
> You don't want any circuit current in the shield, intentional or
> incidental.
> IBM in conjunction with State Farm did find some value in bonding
> machine frames together, particularly when they were separated by long
> data cables but this was a separate 16 ga or larger "drain" wire. (the
> term used so as to not invoke NEC confusion)
> We used this method in a number of places in SW Florida to stop
> lightning damage.
>

Found a good rundown of the types of answers I was looking for on an
uber-expensive vendor's site:
http://www.siemon.com/us/standards/Screened_and_Shielded_Network_Cabling_Guide.asp

Looks like I should be in spec grounding at the patch panel..

Don Hills

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Nov 14, 2012, 7:31:06 AM11/14/12
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How quickly we forget...
IBM Type 1 cabling system, used for Token Ring.
And it shows how quickly I forget - it was centrally grounded,
but I forget the actual details.
--
Don Hills (dmhills at attglobaldotnet) Wellington, New Zealand
"New interface closely resembles Presentation Manager,
preparing you for the wonders of OS/2!"
-- Advertisement on the box for Microsoft Windows 2.11 for 286
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