Greatest Home Network noise is when data is being transferred. Loudest voice signal was S9. Clearly, the interference is being conducted by these wires. Ham Transmitters and broadcast stations. Modest RF levels at 40 meters completely killed this data network.
Replacement is a step in the right direction but the new version has little testing behind it.
But theirs more. Their are several brand new systems coming on the market. The HomePlug Alliance has just been formed which attempts to use AC power lines to transport data around the home. Passing communications over power lines as been attempted for years and no one has really done well at it except for very low data rates. We all need to keep a careful eye on these systems.