|Added clip on ferrite chokes (Fair-rite VO) to 120V supply wires (L,N,G). There are at least 2 chokes in series per wire (not all visible).
|At the bottom of this control board we have the wires running to the thermostat upstairs. Disconnecting at the terminals makes it easy to twist the wires (which also adds impedance) as well as add a toroid choke with about 4-5 loops.
|This is the inducer fan motor itself. Disconected pigtail to twist wires and added 3 clip on chokes in series.
|Another view: chokes added to inducer fan wiring. Where there was room I added a choke per individual wire. Sometimes the chokes went over multiple wires; both ways add impedance.
Before this filtering every time the furnace came on 40m and above were wiped out by noise. Now it makes no noticeable difference whether the furnace is running or not.