[RFI] Computer birdies

Jim Brown jim at audiosystemsgroup.com
Tue Jun 26 07:24:27 PDT 2012

On 6/26/2012 7:16 AM, Steve wrote:
> Anyone ran into this kind of thing before? Advice as to how to rid
> myself of these unwanted signals?

It's the Ethernet stuff related to the router. The cables are acting as 
transmitting antennas, your ham antennas are receiving the noise.  The 
solution is multi-turn ferrite chokes on each of those cables. Five 
turns on a #43 or #31 core will make a nice dent in the noise.  See 
http://audiosystemsgroup.com/RFI-Ham.pdf  for details, and for part 
numbers and vendors for suitable ferrite cores.  EVERY cable can radiate 
the noise, including the power cables, so every cable should be choked.

73, Jim Brown K9YC

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