How Does Radio Broadcasting Work?

At the station, a microphone turns sound into an electrical signal. A transmitter combines that signal with a high-frequency carrier wave, either by varying its strength (AM, amplitude modulation) or its frequency (FM, frequency modulation). The antenna radiates this as radio waves travelling at the speed of light. Your receiver's antenna picks up many signals, and the tuner selects one frequency and extracts the original audio. AM waves can travel very long distances, especially at night, while FM usually offers clearer, less noisy sound over shorter ranges.