47 CFR § 74.1283 - Station identification.
(a) The call sign of an FM broadcast translator station will consist of the initial letter K or W followed by the channel number assigned to the translator and two letters. The use of the initial letter will generally conform to the pattern used in the broadcast service. The two letter combinations following the channel number will be assigned in order and requests for the assignment of particular combinations of letters will not be considered.
(b) The call sign of an FM booster station or LPFM booster will consist of the call sign of the primary station followed by the letters “FM” or “LP” and the number of the booster station being authorized, e.g., WFCCFM-1 or WFCCLP-1.
(c) A translator station authorized under this subpart shall be identified by one of the following methods.
(1) By arranging for the primary station whose station is being rebroadcast to identify the translator station by call sign and location. Three such identifications shall be made during each day: once between 7 a.m. and 9 a.m., once between 12:55 p.m. and 1:05 p.m. and once between 4 p.m. and 6 p.m. Stations which do not begin their broadcast before 9 a.m. shall make their first identification at the beginning of their broadcast days. The licensee of an FM translator whose station identification is made by the primary station must arrange for the primary station licensee to keep in its file, and to make available to FCC personnel, the translator's call letters and location, giving the name, address and telephone number of the licensee or his service representative to be contacted in the event of malfunction of the translator. It shall be the responsibility of the translator licensee to furnish current information to the primary station licensee for this purpose.
(2) By transmitting the call sign in International Morse Code at least once each hour. Transmitters of FM broadcast translator stations of more than 1 watt transmitter output power must be equipped with an automatic keying device that will transmit the call sign at least once each hour, unless there is in effect a firm agreement with the translator's primary station as provided in § 74.1283(c)(1) of this section. Transmission of the call sign can be accomplished by:
(i) Frequency shifting key; the carrier shift shall not be less than 5 kHz nor greater than 25 kHz.
(ii) Amplitude modulation of the FM carrier of at least 30 percent modulation. The audio frequency tone use shall not be within 200 hertz of the Emergency Broadcast System Attention signal alerting frequencies.
(d) FM broadcast booster stations shall be identified by their primary stations, by the broadcasting of the primary station's call signs and location, in accordance with the provisions of § 73.1201 of this chapter.
(e) The Commission may, in its discretion, specify other methods of identification.