A
hobby popular with
geeks before computers. There are over a half-million
hams in the world.
In the US, to become a ham operator you must get a license from the FCC and set up a radio station, which may transmit up to 1500 watts.
Many advances in radio communication came about because of experiments by hams, and they have been helpful in hundreds of emergency situations.
For more information contact the ARRL.