(Amplitude Modulation radio) Radio broadcasting in the 540-1610 kHz frequency band (in the Americas) with 10 kHz spacing between channels. AM technology modulates a carrier by varying the signal strength, not by frequency as with FM. For 30 years starting in the 1920s, AM flourished in the so-called "Golden Age of Radio." However, starting around the late 1950s, FM's higher fidelity became popular for music listening. Most AM radio stations today broadcast news, talk, traffic and weather. See FM radio and shortwave radio.