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Is this call sign available?
Enter a call sign (AM, FM, LPFM or TV) and see what the FCC's station records say: the current holder, whether it was recently given up, and whether FCC rules would allow it.
Nothing in mind yet? See all the unused K and W call signs.
WDOI
LMS shows it available, but a ship uses it
No broadcast station holds WDOI, so the FCC's LMS search will show it as available. But WDOI is the call sign of an FCC-licensed ship (compulsory equipped: cargo, passenger, commercial), license active through June 14, 2027. Expect the request to be refused or changed later.
Why: Four-letter K and W combinations assigned to ships or other radio services are not available to broadcast stations, with or without -FM, -TV or -DT (47 CFR 73.3550(k); the FCC kept this word for word when it last amended the section in 2024). The FCC's original call sign system flagged ship calls (FCC 98-324, paragraph 14); today's LMS search doesn't check ships, so it may let you reserve one that the FCC can later change (47 CFR 73.3550(g)).
Ship licenses with this call sign
| Call sign | Type | License | Dates | Links |
|---|---|---|---|---|
| WDOI | Ship (compulsory equipped: cargo, passenger, commercial) | Active | granted June 14, 2017, expires June 14, 2027 | FCC record |
- K call signs go to stations west of the Mississippi River, W call signs east (47 CFR 73.3550(e)).
- Checked against FCC-licensed ships and shortwave stations, which the FCC's own LMS search doesn't check. Federal ships (NOAA, Military Sealift Command) get their call signs from NTIA and aren't in any FCC file, so they can't be checked here (47 CFR 73.3550(k)).
Looking for ideas? See every spare WD call sign or browse all prefixes.
FCC LMS station records as of October 16, 2026. Reserve call signs in LMS, which has the final word.
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.