[RFI] RFI LG Refrig Corcom filter and #31 core

[Jim Brown]

On 9/29/2021 2:28 PM, Dan K2YWE wrote:
> Thanks. I was thinking it's good to have shunt paths to ground, like the 
> Corcom will have, to add to the effectiveness of the choke.

A very common cause of RFI from most equipment is failure of the Green 
Wire to make proper contact with the chassis where it leaves the 
equipment. It's the power line equivalent of the Pin One Problem. That's 
what puts RF on the Green wire, which then acts as a transmitting 
antenna for the noise.

Filters like the Corcom only work on noise that's on Phase and Neutral. 
But the act of bonding the filter's Green Wire to the chassis is 
important, both because it keeps RF off the Green Wire by that 
mechanism, and because it makes the filter work better on trash that's 
on phase and/or neutral.

It's also important to realize that what the EMC regs world call common 
mode is noise between neutral and Green. What WE call common mode is the 
algebraic sum of the current coupled onto a cable, and what we call 
common mode is what excites the cable as an antenna.

73, Jim K9YC