[CQ-Contest] CQWWSSB weird noises on 10 M and other bands

Jim Brown k9yc at audiosystemsgroup.com
Tue Nov 1 20:55:31 EDT 2022

On 11/1/2022 3:38 PM, kq2m at kq2m.com wrote:
> The other type of noise was what I'll call a "Squiggler" which was loud 
> and about 3 - 5 khz wide.

Hi Bob,

You may be hearing high order harmonics of the square waves in a 
switch-mode power supply (SMPS) which are ubiquitous -- there are at 
least a couple of dozen in the typical US home -- or some power control 
electronics, like a variable-speed controller for a motor.

Study this applications note, which ran several years ago in NCJ as a 
two-parter. It provides lots of ideas about figuring out the type of 
noise you're hearing, how to find the source, and how to kill (or 
reduce) the noise.


73, Jim K9YC

More information about the CQ-Contest mailing list