Back in the late 1980s I had the same problem with a Ham Radio Operator just a few houses away. I bought a 31" console TV that had a synthesized surround sound amplifier. When I hooked up a pair of remote rear speakers to the TV it didn’t sound all that bad. That was until the Ham operator decided to dust off his radio and start transmitting again. Every time he keyed the mic and spoke I could hear his garbled voice through not only the two rear speakers but the front speakers in the Console TV. Even with the TV turned off I could still hear the guy when he was using his radio, though not as loud when the TV was turned on. The guy’s garbled voice did not change with the sound volume setting of the TV.
Problem ended up being the two speakers cables that ran around the wall of the room to the rear speakers. The two cables were working as an antenna and picking up the Ham Operator’s transmitted signal.
I tried everything. Ferrite beads on the power ac cord. Ferrite beads on the two rear speaker cables at the two speakers. Filter caps, at the speaker terminals. A factory made 95% shielded twisted pair cable for the speaker cables. Nothing helped.
I finally disconnected the rear speaker cables from the TV. With the rear speaker cables disconnected, the front speakers in the TV worked fine. Not a hint of the Ham’s garbled voice.
In james1969 other running thread I mentioned he might try wrapping some aluminum foil around the speaker cables feeding his 2 speakers. Not sure if he tried it or not. I am not sure the aluminum foil will even help.https://forum.audiogon.com/discussions/high-frequency-intermittent-noise
As for ferrite beads and filter caps. Don’t they have to be selected for the frequencies you are trying to block, reject?