The FCC administers and maintains licenses for AM, FM, LPFM, FM translator and FM booster radio stations. FM radio licenses are available for operators of full power commercial stations, as well as full and low power, noncommercial education stations. A license is required to operate a radio station, and can be obtained by filing an application with the FCC. The commission must approve a proposed radio license assignment prior to the sale of the station. The FCC provides public notice of the filing of all new station, assignment and license renewal applications. This public notice starts a 30-day period for the public to file comments or objections to these applications.
FM is short for frequency modulation, which refers to the means of encoding the audio signal on the carrier frequency. FM full power, low power, translator and booster stations operate in the 88 – 108 MHz band. There are many classes of radio stations. The smallest provide service to areas within three or four miles of a transmitter site; the largest provide service to locations more than 60 miles from a transmitter site. Only noncommercial educational radio stations are licensed in the 88-92 MHz “reserved” band. Both commercial and noncommercial educational stations may operate in the “non-reserved” 92-108 MHz band.
AM is short for amplitude modulation, which refers to the means of encoding the audio signal on the carrier frequency. In many countries, AM radio stations are known as "mediumwave" stations. They are also sometimes referred to as "standard broadcast stations" because AM was the first form used to transmit broadcast radio signals to the public. Over one half of all Many AM stations are either daytime-only stations or stations authorized to operate at very low power levels at night as a result of “sky wave” propagation, which occurs when the AM signal is reflected off the ionosphere and back to the earth.