[RFI] Noise changes when room lights turn on / off

[Jim Brown]

On 9/15/2012 5:22 AM, Eddy Swynar wrote:
> Incredibly, the coiled handset cord while I was seated was immune to RFI---but as soon as it was outstretched, it must have acted like a resonant loaded vertical on 10-meters!

Why do you use the word "incredibly" to describe simple antenna action?

> No amount of handset bypassing / filtering ever eliminated the RFI in the cord's uncoiled state

This might have succumbed to a couple of turns around a #43 or #31 
ferrite core placed either on the cord to the handset, or to the 
telephone line cord.

FWIW, telephones are notoriously bad for RFI.

These RFI "war stories" are quite useful, including Pete's about those 
light switches.  There's clearly something about the construction of 
those switches that is allowing noisy leakage current when the switch is 
off, and interior house wiring is radiating it.

73, Jim K9YC