ferrite cores against EMI
ferrite cores against EMI, interference protection
The easiest and most successful way for RFI suppression is the detuning of the device leads ( power cord , antenna cable ,
telephone cable, speaker cable , etc.). The best here are toroidal cores from high-resistance ferrite material (preferably nickel - zinc)
and a high permeability from about 800. The respective leads are wrapped several times through the ferrite core.