Amateur radio, commonly called "ham radio", is a hobby enjoyed by many people throughout the world, about 3 million worldwide and 700,00 in the USA. The owner of an Amateur Radio license has studied and passed required tests in their country and then issued a call sign by their government. This call sign is a unique to the person and is a source of pride - and the holder of the call sign uses their call sign on the air to make their legal identification during communications. Amateur Radio should not be confused with CB radio which is limited in modes of operation and unregulated in most countries.
Licensed Amateur Radio operators enjoy personal two-way communications with friends and family members, who are also licensed. And they support the larger public community with emergency and disaster communications. Increasing a person's knowledge of electronics/radio theory and radio contesting are also popular aspects of this radio service/hobby. For more info on Amateur Radio and the related call signs - explore the many links at these web sites: ( http://www.arrl.org/ ) and ( http://www.qrz.com ).
Within amateur radio, one can pursue interests such as providing the communications for a community emergency response team; antenna theory; satellite communication; disaster response; Skywarn; packet radio (using data transmission similar to the internet, but by radio); DX communication over thousands of miles using the ionosphere to refract radio waves; Internet Radio Linking Project (IRLP); and super low-power or QRP operation.
One of the more exciting activities of ham radio is a DX-pedition. Radio amateurs collect QSL cards from other stations, indicating the continents and regions that they have contacted. Certain zones of the world have very few radio amateurs. As a result, when a station comes on the air with a rare station ID, radio amateurs flock to communicate with it. To take advantage of this phenomenon, groups of hams transport radio equipment into a remote country or island (such as Bouvet Island, which has the rare prefix 3Y). These expeditions can help hams quickly achieve a communication award such as a DXCC. To obtain the DXCC award a ham needs confirming QSL cards from hams in 100 countries around the world.
See also Morse code, electromagnetism, Electromagnetic radiation, Q Code, SSTV, country codes, callsigns.
For more information, please see http://www.arrl.org . With the advent of the internet (offering email, music, broadcast audio, video, voice over IP VoIP) the popularity of ham radio is diminishing somewhat in advanced countries.