[Ground-station] The other kind of ground

[Zach Leffke]

question on a related topic........I'm getting a lot of EMI/RFI from 
Ethernet from some PoE powered cameras (1Ge rated, but I'm sure they're 
not running that fast, maybe a 1 or 2 Mbps per camera).  The primary 
band that I notice it on is VHF which almost completely trashes the 
spectrum.  I've got 3 cameras with pretty long shielded cat5e runs, with 
shielded RJ45 tips, connected to an NVR.  NVR chassis is connected to 
the rack single point ground which is then connected via strap to the 
shack singlepoint ground out to a grounding network of ground rods.

I was able to isolate the problem to primarily the NVR and 3 cameras 
(everything off, spectrum looks great, turn on NVR, no cameras 
connected, spectrum is trash, plug in camera 1 = more trash, camera2 = 
even more trash, camera3 = most trash).  Other ethernet devices in the 
mix also produce a small amount of RFI (like a serial to ethernet 
converter) but those runs are much shorter and the affect is almost 
negligible (though I would still like to remove the effects if 
possible).  The runs to the cameras are maybe 80+ ft or more.
Kind of annoying because if I want to do 'clean' 2m demos, I have to 
shutoff the NVR, which hurts the overall demo because now I can't 
monitor the antenna motion with the video feed.

Not sure if the junk is getting into the front end of the receive system 
and propagating back to the SDR or if its something coupling in through 
the rack.

Any tips/hints/tricks/ etc. on how to get rid of the 2m trash or at 
least how to troubleshoot would be welcome.  I've looked into Ferrite 
solutions, but not really sure the right place to put them, and not sure 
if that would kill the actual ethernet performance.  Are there any 
particular ferrite type filters I could build for this?  are there 
existing filters on the market for this?


I realize optical would be the way to go, but 1) I loose the PoE feature 
(but could run separate DC power to each camera, so doable) and 2) can't 
afford the converters at the moment.

Thanks in advance!

-Zach, KJ4QLP


On 7/3/2018 3:24 PM, Bruce Perens via Ground-Station wrote:
> Let's all of us hams lead a return to optical fiber for consumer 
> equipment, including data networking. It's easy to show that plastic 
> fiber is potentially cheaper than metal, and LEDs and photosensors are 
> cheaper than a wired Ethernet termination with all of the little 
> ferrites etc. While helping the world, we will incidentally reduce RFI 
> for ourselves.
>
> On Tue, Jul 3, 2018 at 11:42 AM, Douglas Quagliana 
> <dquagliana at gmail.com <mailto:dquagliana at gmail.com>> wrote:
>
>     Hi Bruce,
>
>     New houses are still being built with Cat-5e cabling, if they even
>     have
>     networking cables in the walls. I was going to jokingly suggest
>     skipping
>     the Cat-7 cabling and just waiting for Cat-8, but Cat-8 is apparently
>     almost ready for release. However it is not intended for general use.
>     Cat-8 is only for short runs in the data centers.
>
>     Maybe just wait for Cat-9 cabling or end-to-end fiber without any
>     copper in the data path. After all, it will still be called
>     "Ethernet."  :-)
>
>     Happy 4th everyone,
>     Douglas
>     (Must...Resist...Puns...With...Cats...And...Nines...)
>
>
>     On Tue, Jul 3, 2018 at 12:54 PM, Bruce Perens via Ground-Station
>     <ground-station at lists.openresearch.institute
>     <mailto:ground-station at lists.openresearch.institute>> wrote:
>
>         OK, tell me why I'm an idiot :-)
>         https://perens.com/2018/07/03/how-should-you-ground-your-shielded-ethernet-cable/
>         <https://perens.com/2018/07/03/how-should-you-ground-your-shielded-ethernet-cable/>
>
>         -- 
>         Bruce Perens K6BP - CEO, Legal Engineering
>         Standards committee chair, license review committee member,
>         co-founder, Open Source Initiative
>         President, Open Research Institute; Board Member, Fashion
>         Freedom Initiative.
>
>         _______________________________________________
>         Ground-Station mailing list
>         Ground-Station at lists.openresearch.institute
>         http://lists.openresearch.institute/mailman/listinfo/ground-station
>         <http://lists.openresearch.institute/mailman/listinfo/ground-station>
>
>
>
>
>
> -- 
> Bruce Perens K6BP - CEO, Legal Engineering
> Standards committee chair, license review committee member, 
> co-founder, Open Source Initiative
> President, Open Research Institute; Board Member, Fashion Freedom 
> Initiative.
>
>
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-- 
Research Associate
Aerospace Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
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