A florescent tube emits abuot a 1.3 M hertz buzz. This RF buzz comes from the plasma in the tube. It cuts off sharply on the lower voltage of the AC sine curve. There is a bit of negative resistance at work here too.
Some tubes are about 1 meter in length. Perhaps something may come of my megahertz meter relationship here. could it be? https://www.bobvila.com/posts/190831-light-will-not-turn-off-using-light-switch?page=1#.WhnZPFWnGM8 Frank