[sudo-discuss] Can someone please donate Cat6 Shielded cable?

[max b]

Hey Charley,

You're more than welcome to donate money (or time) if that's more up your
alley. Also, if you want to donate UTP cat6, we'll take that as well. We
use a bunch of ethernet cable both at the omni and for other installations,
so we can always use more. If you're feeling really generous, we can really
use shielded outdoor cat5 and cat6 for installing antennas. Don't worry -
no matter what kind of ethernet cabling you feel like donating, we can
almost certainly find a use for it :)

As for the questions you've outlined:

First thing: shielded cable

This isn't actually an ethernet run. It's dsl lines + phone lines running
over cat copper wires. As such, it's my understanding that it's more
sensitive to EMI disturbance. Additionally, it's much better to err on the
safe side as we'll only want to string this once and the entire network
communications infrastructure depends on the dsl signal that passes through
this line. As for needing shielded mating jacks, we have plenty of grounded
rj-45 connectors and with whatever other scenarios, it's pretty easy to
ensure that they're grounded. We're not talking about our entire network
infrastructure, we're just talking about this one cable run.

Second thing: hand termination

We're using an EZ RJ-45 crimper, which makes the process fairly
straightforward. We have spools of other types of ethernet cables and have
done runs throughout the building. Also - we'll be breaking out these pairs
anyhow, so most of this is fairly non standard types of termination which
are much easier than rj-45 disconnects.


Daniel, let us know if I missed anything here?


Max

On Tue, Aug 25, 2015 at 2:01 AM, Charley Sheets <rcsheets at acm.org> wrote:

> Hey Daniel,
>
> I am interested in helping out, but I have to admit I'm fairly
> skeptical of two elements of this request, so I'd like to get some
> clarification if possible.
>
> First thing: shielded cable. My understanding is that most of the noise
> rejection comes from the twists, not the shielding, and that shielded
> cable is only useful in high-EMI environments. Am I mistaken about the
> application, or are we perhaps in a high-EMI environment? The standard
> example of high EMI is something like a factory floor. Shielding also
> only works as intended if the mating connectors (jacks and whatnot) are
> also shielded. Does that apply here? My inclination is to donate
> standard (UTP) cat6 cable. Please help me understand why I should
> donate shielded cable instead.
>
> Here is some information (could be biased -- it's from a cable
> supplier) about the differences as they apply to cat6a:
> http://mirapath.com/blog/item/cat6a-shielded-or-unshielded
>
> Second thing: hand termination. You've stated a preference for a box of
> several hundred feet of cable. To me that implies that you'd prefer to
> hand terminate the cable rather than having pre-terminated cables. I
> certainly won't make any claims about your personal ability to
> terminate cables, but most people are not especially skilled at this,
> and many hand terminated cables I've seen in the field are visibly not
> well made. I've terminated cat5 and cat5e cable, and it's always been
> very fiddly and challenging for me to minimize the untwisted distance,
> and to ensure there are no open pins. Pre-terminated cable is
> available with strain relief boots and is often certified to be
> complaint with the relevant cabling standard. What do you see as the
> advantage of spools of cable? Why not buy pre-terminated cable?
>
> I hope this doesn't come across as overly critical. Sorry if it does. I
> really just want to make sure we get exactly what we need.
> --
> Charley Sheets
>
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