Radio and Signal Hobbies

Hobbies built around transmitting or receiving radio signals, a maker-and-tinkerer hobby in Stebbins' typology crossed with a technical-listening variant. Belongs here: amateur radio (licensed two-way transmission) and shortwave listening (receive-only monitoring of distant broadcasts). Does not belong here: model aircraft and other hobbies that merely use radio control as one tool among several, grouped under Model Building and Flight Hobbies.