Shielded RJ-45: Internal vs External Ground?

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I have seen the light and am going to replace the regular Cat5 cables on
my radio links with shielded - using Ubiquiti's ToughCable Pro.

With shielded RJ-45 plugs, I see "Internal" and "External" as in
Internal: http://www.platinumtools.com/products/100020.php?cat=5

External: http://www.platinumtools.com/products/100022.php?cat=5

For somebody who doesn't use that many - as in a hundred being a
lifetime supply - the no-brainer would seem to be the "External" style
because it can be used anywhere, not just with devices that
automagically forward the ground from the shell of the connector their
AC ground wire.

Does this make sense?     Or am I missing something.

Ubiquiti NanoStations with POE Injectors.
--  
Pete Cresswell

Re: Shielded RJ-45: Internal vs External Ground?

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I'm curious, where is this discussion taking place where they're
recommending shielded cable? I wonder what's the basis for the
recommendation. Yes, I'm skeptical.



Re: Shielded RJ-45: Internal vs External Ground?
Per Char Jackson:
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So was I.  

But the manual says that shielded cable is important. viz Page 4 of
http://setuprouter.com/router/ubiquiti/nanostation-m5/manual-877.pdf

Self-serving promo for their house brand?  That was my kneejerk
reaction.... but now I know that there are several threads in the
Ubiquiti fora that make it pretty clear that electrostatic discharge is
a consideration.  For example: http://tinyurl.com/m5vttf3

Now I realize that I cannot afford to be skeptical because I just don't
know enough.
  
The facts are:

- Every so often 3 cams become unreachable from a remote site over
  a radio link.

- A fourth cam never, ever has any problems

- The 3 problem cams immediately become reachable once both
  ends of the radio link are re-booted.

- One of the links is attached to the top of a 15-foot windsurfer
  mast only about 50' from a large bay - i.e. it gets some  
  serious weather.

Add to the above that it is starting to look like there is a correlation
between the failures and high winds at the site and you see where I
am....

But, like I said, I'm clueless except that I know that those three
things are clearly happening....  And the pros on the Ubiquiti site are
telling me that grounded/shielded cable to an outside radio is
absolutely standard practice.

I have withdrawn from the discussion where this is taking place because
I was starting to irritate at least one of the gurus there with my
incessant beginner-type questions.   The guys who matter there  are
mostly professionals and it is now clear to me that I was abusing the
environment.   There are also amateurs there, but I seem to be more
verbose and less inclined to research before asking than most.

But my basic question remains: how can a radio-link problem be
camera-specific?    

Greater Minds Than Mine have said "No problem... see it all the time."

But I have yet to get specifics... to that end, I just pulled the
trigger on a smart switch that I will swap in down at the problem site
when I get down that way.   Then I will be able to test the obvious
suggestion that it is something to do with bandwidth (not!...but I need
to prove it) and also to put WireShark on both ends of the link.

Whatever happens, I am going to come out of this knowing significantly
more than when I went in.

The thread is at: http://tinyurl.com/m6pyfje
--  
Pete Cresswell

Re: Shielded RJ-45: Internal vs External Ground?
wrote:

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Static buildup on metal structures is only a problem when the humidity
is quite low.  My guess(tm) is 20% or less.  That's not a problem in
the bay area, and certainly not in a wet marine environment.

Shielding does do well for EMI/RFI protection.  If you're near a
transmitter of any significant power level, I would use shielded
cable.  Even so, I doubt if it would do any good because most of the
Ubiquiti radios use unshielded plastic case.

Note that there are aftermarket products that provide shielding if
needed.
<http://www.rfelements.com/en/products/shields/rockshield/
If you're using it for cellular backhaul, it's probably a good idea.


--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Shielded RJ-45: Internal vs External Ground?
wrote:

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One more:
<http://www.rfarmor.com
Notice that the listed reasons for installing shielding do not mention
precipitation static, or air friction static buildup.  If you're going
to shield the CAT5, might was well shield everything else (except the
antenna).

Maybe try aluminum duct tape on the inside of the plastic case for
cheap shielding?


--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Shielded RJ-45: Internal vs External Ground?
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Re: Shielded RJ-45: Internal vs External Ground?
On 1/10/2015 8:45 AM, (PeteCresswell) wrote:
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Just a pure guess, but if the wind is that bad at the remote site I  
wonder if the power might not be fluctuating for the same reason.
With the three affected cameras being from the same brand I wonder if  
that brand might be more sensitive to the fluctuations.

If you have a small UPS handy you might want to plug the switch into it  
and see if the problem goes away since it is powering all the cameras at  
the site.

Re: Shielded RJ-45: Internal vs External Ground?
Per GlowingBlueMist:
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I think I have disposed of the wind theory.   It developed when I saw
several failures in a few hours when the wind was gusting into the
forties.    But yesterday I had more instances when there was just
normal wind.

I'll take the UPS suggestion though...
--  
Pete Cresswell

Re: Shielded RJ-45: Internal vs External Ground?
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Re: Shielded RJ-45: Internal vs External Ground?
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