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Call sign availability

Clear a call sign before the request goes in: current holder, recent release, and how the rules apply.

Nothing in mind yet? See all the unused K and W call signs.

The rules behind broadcast call signs

Newly assigned AM, FM and TV calls have four letters. They begin with W on the east side of the Mississippi River and K on the west side, adding -FM, -TV or -LP (LPFM) where required; LPTV stations take -LD, while Class A TV uses -CD. Once a station holds a construction permit it requests its call through LMS at the FCC, and requests are filled first come, first served.

No waiting period applies: as soon as a station's call change takes effect, anyone may reserve the old call. Commonly controlled stations may use one base call across services (for example KXXX-FM alongside KXXX); in any other case, using a different station's base call in another service requires the other station's consent. Translators for FM and TV cannot choose: their calls are assigned in sequence (K or W, then the channel, then two letters).

Ships, mostly large commercial vessels, are also assigned K and W calls with four letters, and a broadcast station cannot use a call that is assigned to a ship. Ship calls used to be flagged by the FCC's first online call sign system, but the current LMS search looks only at broadcast stations and will report a ship's call as "available". This check covers every FCC ship license carrying a four-letter call, plus international shortwave broadcasters on the FCC's list (WWCR, WRMI, KNLS and others), flagging them in amber. Federal vessels (NOAA, the Military Sealift Command) receive calls from NTIA and do not appear in FCC records, so verify in LMS before filing.

Sources

  • 47 CFR 73.3550: LMS requests, the K/W split at the Mississippi, four-letter calls and their suffixes, secondary and shared calls, and ship calls.
  • 47 CFR 74.791, also 74.1283: call signs for LPTV, Class A and translator stations.
  • FCC 98-324 (1998), at paragraph 16: once a call change takes effect, the old call is open to others.
  • Station data come from the FCC's public LMS database (call sign requests and facility records), refreshed each morning.
  • Shortwave stations: FCC-authorized international broadcasters from the FCC High Frequency Stations list (Subpart F of 47 CFR Part 73).
  • Ship data: weekly FCC ULS ship license files, with ship types decoded using the ULS radio service codes.

The FCC did not make this tool. Need to reserve a call sign or file for a station? Nexus Broadcast handles FCC filings and engineering.