 The first radio transmitters used a loud spark gap to generate radio waves, and so were often housed in a separate outbuilding or shed.When radio was first adopted by the U.S. Navy, a small, wooden structure placed on deck to house the ship's radio equipment became known as the "radio shack".Today, a radio shack can be anywhere that radio equipment is housed and operated, usually a room such as with amateur radio stations, but for some the entire "shack" may consist of a hand-held radio or two while others may operate mobile equipment in a vehicle.