go to the fi-shock electric fence website they may have some answers for you.
I am plauged by a neighbor's electric fence but I'm lucky cause they let me service it.
1. be sure the ground rod is an 8 foot 5/8 ul approved type home depot has them a short hunk of rebar is not a good ground!
2. ensure you have a 3 wire cord and you install bypass capacitors the electric fence folks do not because they won't spend the dollar in parts!
3.walk the wire any loose connection or splice will chatter I use a brass splice/crimp and then use the western electric style of splicing wires...that is tightly twisting the wires one side in one direction the other side the opposite direction. then as the wire is pulled the connection tightens
good luck you'll never eliminate the noise completely
the timewave anc-4 helps some but is not a cure.
I also have a tig welding qrm issue from a guy that has a body repair shop in his home yep! allowed by the city so it's there!
regards, marty email@example.com