I have a lot of noise on my system so am building one of GM3SEK's RF filters to see if it will help.
I have wrapped the flex cables in a clip-on ferrite and two glued-together ferrites.
I connected the incoming mains via a large kill switch. :
and then put the components for the filter into a box. Schaffner FN 2030-16-06 LINE FILTER REF13 into the filters, then out to a mains multi-way power outlet.
I've not activated this yet as I'm planning a shack move-around. Will update the post with results!