Just out of curiosity, what kind of ballast(s) were you using that created interference?
I've had the cable company come to my place twice saying there was interference.
They actually showed me the interference on a laptop graph. I started freaking but then remembered the lights hadn't kicked on yet, I generally start mine around 4 PM.
They tightened my cable connections, including one in the living room and their spikey graph flat lined. They said everyone down line from me was affected.
I'd like to get some kind of tester for that shit, got testers for every other thing. I should have asked the cable guy, but I was too busy playing dumb.
A ham radio picks that shit up? I always wanted a ham radio.