An
antenna ball or a
corona ball is a round metal
sphere usually attached to the free end of
transmitting
antennas, most often
whip antennas. As the
electric current tends to a minimum at the end of the antenna, the
voltage tends to reach a maximum. Very
sharp or
pointy features tend to result in very high electric field at those points; coupled with the high voltages at the end of the antenna, this can cause the air near the end of the antenna to
ionize creating corona. With sufficient transmitter power, this can cause the end of the antenna to
melt from the
heat.
Bad. Placing a round object at the end of the antenna eliminates the sharp protrusion, and greatly reduces corona.
yep, those balls are there for a reason...