The whole problem with RF interference though, is that y, just like a radio or TV transmitter. You can't eliminate it with a power conditioner. RF can not get through the equipment's transformers. The problem is devices like dimmers radiate RF back into the mains cable. It can be your neighbors dimmers and motors too. Any one on the same secondary of the nearest transformer as you, can radiate RF interference into your home. The mains cable then becomes a transmitter through the air. Your equipment receives this as radio waves through the air, just like you radio set does. You have to go into a different mode altogether to deal with RF. You have to think way beyond power conditioners. To stop RF with a power conditioner, it would have to be right were the supply comes into your house, and big enough to handle your whole house current.
You have to keep speaker cables, which are so often the entry point for radio waves from being near power cables, and not having them run parallel with mains cables if possible.
Make sure screens are in good condition. An oxidized RCA jack can be a source of penetration, as the oxide layer can act as a semiconductor, and start the rectification of radio waves at the connector. Sometimes changing the physical orientation of an amp preamp or receiver makes a difference as it can reduce the pick up by the part receiving the interference. This is just like rotating an antenna to receive a radio stations signal better.
Radio frequency interference is a tough problem. He is in Australia, that uses a higher voltage grid. He will be sharing his electric circuit with far more people than in the US, as I explained previously.
