[Ground-station] The other kind of ground

Tue Jul 3 13:02:14 PDT 2018

Zach,

I live in a RF quiet place and have had really serious issues with RFI. For
some time I have tried using ferrite on power and network cabling, but the
results were mediocre. I have now banned wired Ethernet and use WiFi for
LAN and optical fiber for LAN (SDR) and WAN. I have also banned some PC
monitors and switched power supplies. Some monitors generate RFI that looks
like white noise on VHF and and UHF. Some switched power supplies make
havoc on HF. For computers, I try to avoid desktops. Laptops "tend" to be
generate much less RFI. From the ones I've tested, the types made by Apple
and Dell tend to be the quieter ones.

73,

Edson PY2SDR

On Tue, Jul 3, 2018 at 4:35 PM, Zach Leffke via Ground-Station <
ground-station at lists.openresearch.institute> wrote:

> 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>
> 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> wrote:
>>
>>> OK, tell me why I'm an idiot :-) 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
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>>>
>>>
>>
>
>
> --
> 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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>
>
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> Aerospace Systems Lab
> Ted & Karyn Hume Center for National Security & Technology
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