List of three-letter broadcast call signs in the United States
This is a list of radio and television broadcasting stations in the United States that are currently assigned three-letter call signs.
Overview
In the United States, all radio and television broadcasting stations that are licensed by the Federal Communications Commission are assigned official, unique call signs. Organized broadcasting began in the U.S. in the early 1920s on the AM band — FM and television did not exist yet. Initially most broadcasting stations were assigned three-letter calls; however, a switch was made in April 1922 to primarily four-letter calls, after the number of stations had increased into the hundreds. For a few years thereafter a small number of new three-letter calls continued to be issued. Although most of the original three-letter calls were randomly assigned, these later calls were often specially requested to match station slogans. The last new three-letter call was assigned to station WIS in Columbia, South Carolina on January 23, 1930. Since then, three-letter calls have only been assigned to stations, including FM and TV, which are historically related to an AM station that was originally issued that call sign.This review only includes FCC-licensed stations. Not included are unlicensed operations, such as carrier current, cable TV, and Internet stations — for example, San Diego State University's "KCR" — which have adopted call-letter-like identifiers that are not officially issued by the FCC. Also not included are stations which use, as slogans, three-letter truncations of their official four-letter call signs; for example, the full call sign for radio station "KOH" in Reno, Nevada is actually KKOH, and "WTN" in Nashville, Tennessee is actually WWTN. In addition, stations which formerly had three letters but have since changed are not listed.
As of December 2025, there are a total of 101 AM, FM and TV stations in the United States that are assigned three-letter call signs. This is divided among only 67 different three-letter calls, because in many cases the same call sign is used by more than one station, although a given call sign is never assigned to more than one AM, FM or TV station. These 67 different three-letter call signs are currently grouped as follows:
- 25 AM-only
- 8 FM-only
- 7 TV-only
- 13 AM/FM
- 7 AM/TV
- 7 AM/FM/TV
Current assignments
Listed below are all the assignments as of December 2025.- All three-letter call signs originated with an AM-band station in the period 1921 to 1930. In some cases, this station subsequently changed to a different call sign. In these cases, the original station, and its latest call sign, is listed in parentheses
- In cases where an AM station exists with the same "base" call letters as an FM station, the FM station is required to include an "-FM" suffix as part of its call sign. If no AM station is currently using the same base call sign, then the "-FM" suffix is optional.
- As with FM stations, if an AM station currently exists with the same "base" call, a TV station must include a suffix to differentiate itself, but this suffix is optional if no AM station currently exists. TV stations may select either "-TV" or "-DT" as their suffix.
Former FM and TV station usage
In all cases, a given three-letter call sign originated with an AM band station. However, the later development of FM and TV stations saw many adopting a version of the well established AM station's call sign. This was particularly true of FM radio stations, which commonly simulcast an AM station before adopting their own formats and distinctive call letters.An FM station example was WDVE. TV station examples include KSDK, KFOR-TV, KGAN, KWQC, WWOR-TV, and WSMV-TV.
Other stations of note
- WWV - Fort Collins, Colorado — shortwave time signal data radio clock service operated by the National Institute of Standards and Technology
- KPH - Bolinas, California — shortwave morse code data service operated by radiomarine.org under the auspices of the National Park Service