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

[Edward Mccann]

This overview came over the transom today. Interesting background, supporting what our RFI gurus have been saying.

Passed for information.

http://images.link.pentondes.com/Web/PentonDES/%7B31de5541-facc-4790-8147-385e74703ca2%7D_wp-design-by-desense-workflow-interference-free-design-electronic-devices.pdf

73,
AG6CX

Sent from my iPhone

> On Mar 28, 2018, at 11:34 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
>> On 3/28/2018 11:22 PM, Jeff Blaine wrote:
>> 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.
> 
> Hi Jeff,
> 
> I have no equipment recommendations, but can at least offer these thoughts.
> 
> Unfortunately, shielding requires FAR more than putting circuitry in a conductive enclosure. Many such boxes are "clamshells" with paint insulating the places where they SHOULD meet, so they're not really shielded. Every cable SHIELD that enters a shielding enclosure must be bonded to the enclosure AT THE POINT OF ENTRY. Any unshielded conductors must go through feed-through caps that shunt RF to the chassis, but doing that with data circuits would likely trash the data. :) This problem can be solved by one or more ferrite common mode chokes on the cable.
> 
> 73, Jim K9YC
> 
> 
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