[RFI] Smoothfitness 6.25 Treadmill RFI

[Jim Brown]

On Tue,9/13/2016 8:44 AM, Lionel Booth wrote:
> My question to the group is whether there is any specific experience with this manufacturer as guidance when I rip into this monster?


Lionel,

The noise is produced by a switch-mode power supply inside the unit, and 
is probably radiated as a common mode signal by the AC wiring. That part 
of it can be killed by winding the power cord through one or more #31 
Fair-Rite cores to form a common mode choke. Follow the guidelines in 
Chapter 7 of k9yc.com/RFI-Ham.pdf for the bands where you hear the 
noise, and for coax the size of the power cable. That is, if the power 
cable is the diameter of RG59/RG8X, use the guidelines for that coax.

There may be more noise radiated from internal wiring. For that, you'll 
need to go inside the box.

AC line filters are a waste of money for this sort of problem.

73, Jim K9YC