I don't know about calling it a broadband RF signal even though I guess you could say there is a similarity between a power line radiated harmonic and an RF signal. I've always heard the regular power line emission called Power Line Radiation (PLR) or Power Line Magnetic Radiation (PLMR), and the real problem for receivers would occur when there is some sort of line problem which could cause harmonics of varying frequencies which is termed Power Line Harmonic Radiation (PLHR). PLHR can cause interference problems with nearby electronic devices. I've experienced this problem firsthand with communications equipment while near a problematic power line. It's been a while, but I believe that PLHR is the correct term. If I'm mistaken maybe someone will correct me.