[RFI] Mobile RFI Help Please

Jim Brown jim at audiosystemsgroup.com
Sat Sep 3 15:25:49 PDT 2011

On 9/3/2011 2:23 PM, Mack McCormick wrote:
> All ideas on how to fix my spark plug RFI are most gratefully appreciated.

If you haven't already done so, wind a multi-turn ferrite choke on the 
antenna cable very close to the antenna.  Use the guidelines in 
http://audiosystemsgroup.com/RFI-Ham.pdf for RG8X-size coax, optimized 
for the bands where the noise is worst.  This will kill any noise that 
might be getting picked up on the coax.

One chronic problem with modern cars is that their bodies are badly 
bonded, often due to too much paint in the way, and to the use of 
non-metallic materials. This can contribute to the noise problem, and 
also to RFI to/from the vehicle's electrical and computer systems.

73, Jim K9YC

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