On Wed, 11 Aug 2010 19:13:45 -0500, Stuart Rohre wrote:
>Some of the problems with audio on the neighbor's side can be poorly
>shielded audio cables. Some RCA cables are more like two conductor
>cables rather than an enclosing shield.
Yes, audio cables are crummy, but that's rarely the cause of RFI.
It's the PIN 1 PROBLEM in the equipment, and virtually ALL consumer
equipment, computer equipment, and ham equipment is built with pin 1
problems. Once the pin 1 problem has coupled RF into the box, it's
detected at the first semiconductor junction it hits, then amplified
and comes out the speakers.
THAT'S why ferrite common mode chokes fixes the RFI -- it kills the
RF current on the cable, which prevents it from exciting the pin 1
problem. In fact, if it were a SHIELDING problem, the choke would not
help.
73, Jim K9YC
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