My only light bulb QSO was in 1965. I had a Globe Scout transmitter, and was using a 60 watt bulb as a dummy load. Probably appropriate for the dummy operator. Anyway, I sent a couple of tests and my call on 15 meters, mostly to watch it flicker. A YV5 came back. I wish I had a picture of the look on my face. 73s, Alan WA4SCA