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Re: [RFI] ethernet switch with shielded case or low emission spectrum

To: rfi@contesting.com
Subject: Re: [RFI] ethernet switch with shielded case or low emission spectrum
From: Jeff Blaine <KeepWalking188@ac0c.com>
Date: Thu, 29 Mar 2018 23:28:44 +0800
List-post: <mailto:rfi@contesting.com>
I don't need to guess the Ethernet spur frequencies - thanks to Murphy they seem to be on MY QRG automagically!!!  :)

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 29-Mar-18 11:08 PM, Dave Cole (NK7Z) wrote:
Take a look at:

https://www.nk7z.net/rfi-snapshots/

just below the first image of Ethernet RFI is a list of frequencies you can expect to find Ethernet RFI on...

Also, if anyone has images of KNOWN RFI sources, please shoot them to me off list and I will include them on the RFI Snapshots page.

73s and thanks,
Dave
NK7Z
https://www.nk7z.net

On 03/29/2018 07:16 AM, Chris wrote:
That's what I hear as well...birdies spaced evenly across the band(s).  Not s9 or anything like that, but still real annoying!!  I guess that is the price we pay for modern technology.

Chris
KF7P


On Mar 29, 2018, at 8:13 AM, jonie41 jonie41 wrote:

Our ADSL modem is in my shack sitting on top of my computer. I use Ethernet to the shack computer, a four bay NAS and two 50ft runs of CAT5 to two other computers located quite close to the shack. Yes, if I find a quiet spot on a band and it coincides with a birdie, I can just hear the birdie, if I shut down
the computer, all goes quiet.

Could I just be lucky or possibly ignorant of the level of RFI?

John
VE3KKQ

---------- Original Message ----------
From: Chris <EZRhino@fastmovers.biz>
Date: March 29, 2018 at 8:59 AM


Hi Jeff,

I've got an ethernet line from a rooftop dish coming into my shack along with the other incoming coax lines, and the router was right there behind my shack
desk.  No amount of ferrite at multiple places along the ethernet
cable--before the router, after the router, on the power cord, etc.--would make any difference on the noise heard on the radio.  Even shielded cat5 didn't help.  My solution was the run the router away from the shack, just a dozen feet or so into the other room, and then use wifi to get internet to my computer instead of a direct connection.  Ethernet is a horrible thing for
RFI!

Good luck.

Chris
KF7P



On Mar 29, 2018, at 12:22 AM, Jeff Blaine wrote:

In the process of overhauling the shack's wiring, I'm wanting to replace my existing ethernet switch with a box that is properly shielded - or at least has one with a low emission footprint. Here i'm talking about radiation from
the box itself - not via the connected ethernet lan cable runs.

Unfortunately the houses' home-run location terminates a few feet from my shack and so the switch needs to be located there.  I can apply ferrite / common mode treatment to the power supply and lan cables that connect to the
box.  But I also need a box that is properly shielded from a ham
point-of-view.  The switches I have now are all of the plastic-case variety
and they all are pretty noisy.

I was hoping someone may have found a "quite" switch that could be
recommended.  Some of the semi-pro (e.g. Netgear home-office rack mount) stuff has metal cases -- but I don't know if that actually means they are
quieter.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

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