Radio transmission is the transmission of signals, usually AUDIO signals, through the airwaves. It is typically done using radio waves, which are electromagnetic waves that travel through the air at the speed of light. Radio transmission is used for a variety of purposes, including broadcasting music and news, sending messages, and providing communication between two or more people. The two crossword solutions for the term radio transmission are 'SIGNAL' (6 letters) and 'AUDIO' (5 letters). SIGNAL refers to the type of wave used to transmit the AUDIO, while AUDIO refers to the type of content being transmitted.