Years ago I used to use a 100 watt light bulb for dummy load and the rig
was a pair of 807's in the final modulated by another pair. Once I was
testing into the light bulb and when I finished, I listened on the frequency
and heard some hams complaining about "that idiot who keeps testing without
listening and never identifies." This was back when the vast majority of
hams ran AM, and the guys complaining about me were on AM. They were about
90 miles away!
Today I have a 2000 watt dummy load made up of glo-bar resistors.
Apparently it doesn't radiate, since I have never had anyone reply when I
accidentally transmitted into it, having forgot to switch back to the
antenna.
-k4kyv