Invalid Call Sign Requests
Last updated Thursday, May 21, 2026 5:54:10 AM (Arizona)
Thursday, May 21, 2026 12:54:10 PM (UTC)
Applications
Invalid Call Signs
This page shows the FCC guidelines for calls which are not available for requesting on an FCC application followed by the invalid call signs which have been requested in the last month and the rule they are in violation of.
The following call signs are not available for assignment and therefore any request for call signs in the following categories are invalid and will be denied.
- KA2AA-KA9ZZ, KC4AAA-KC4AAF, KC4USA-KC4USZ, KG4AA-KG4ZZ, KC6AA-KC6ZZ, KL9KAA- KL9KHZ, KX6AA-KX6ZZ;
- Any call sign having the letters SOS or QRA-QUZ as the suffix;
- Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU);
- Any 2-by-3 format call sign having the letter X as the first letter of the suffix;
- Any 2-by-3 format call sign having the letters AF, KF, NF, or WF as the prefix and the letters EMA as the suffix (U.S Government FEMA stations);
- Any 2-by-3 format call sign having the letters AA-AL as the prefix;
- Any 2-by-3 format call sign having the letters NA-NZ as the prefix;
- Any 2-by-3 format call sign having the letters WC, WK, WM, WR, or WT as the prefix (Group X call signs);
- Any 2-by-3 format call sign having the letters KP, NP or WP as the prefix and the numeral 0, 6, 7, 8 or 9;
- Any 2-by-2 format call sign having the letters KP, NP or WP as the prefix and the numeral 0, 6, 7, 8 or 9;
- Any 2-by-1 format call sign having the letters KP, NP or WP as the prefix and the numeral 0, 6, 7, 8 or 9;
- Call signs having the single letter prefix (K, N or W), a single digit numeral 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and a single letter suffix are reserved for the special event call sign system.
| Call Sign | Rule Violation |
|---|---|
| ` | Call sign is incorrectly formatted as per FCC Guidelines |
| A0FG | Call does not fall within a valid group as per FCC Guidelines |
| A0JG | Call does not fall within a valid group as per FCC Guidelines |
| A1FG | Call does not fall within a valid group as per FCC Guidelines |
| A3FG | Call does not fall within a valid group as per FCC Guidelines |
| A3GEV | Call does not fall within a valid group as per FCC Guidelines |
| A4DHK | Call does not fall within a valid group as per FCC Guidelines |
| A4DJF | Call does not fall within a valid group as per FCC Guidelines |
| A4DK | Call does not fall within a valid group as per FCC Guidelines |
| A5JLS | Call does not fall within a valid group as per FCC Guidelines |
| A7FG | Call does not fall within a valid group as per FCC Guidelines |
| AT5F | 3. Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU) |
| AX0G | 3. Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU) |
| B0RG | Call does not fall within a valid group as per FCC Guidelines |
| B4DJF | Call does not fall within a valid group as per FCC Guidelines |
| C4DJF | Call does not fall within a valid group as per FCC Guidelines |
| COCO | Call sign is incorrectly formatted as per FCC Guidelines |
| D4DJF | Call does not fall within a valid group as per FCC Guidelines |
| E4DJF | Call does not fall within a valid group as per FCC Guidelines |
| F4DJF | Call does not fall within a valid group as per FCC Guidelines |
| G4DJF | Call does not fall within a valid group as per FCC Guidelines |
| G7FWB | Call does not fall within a valid group as per FCC Guidelines |
| G7FWD | Call does not fall within a valid group as per FCC Guidelines |
| G7FWK | Call does not fall within a valid group as per FCC Guidelines |
| G7FWT | Call does not fall within a valid group as per FCC Guidelines |
| G7FWV | Call does not fall within a valid group as per FCC Guidelines |
| H4DJF | Call does not fall within a valid group as per FCC Guidelines |
| I4DJF | Call does not fall within a valid group as per FCC Guidelines |
| J4DJF | Call does not fall within a valid group as per FCC Guidelines |
| K5GRIM | Call sign is incorrectly formatted as per FCC Guidelines |
| K7IDARE | Call sign is incorrectly formatted as per FCC Guidelines |
| KCI8U | Call sign is incorrectly formatted as per FCC Guidelines |
| KCI8Y | Call sign is incorrectly formatted as per FCC Guidelines |
| KKI8B | Call sign is incorrectly formatted as per FCC Guidelines |
| KKI8C | Call sign is incorrectly formatted as per FCC Guidelines |
| KKI8U | Call sign is incorrectly formatted as per FCC Guidelines |
| KKI8Y | Call sign is incorrectly formatted as per FCC Guidelines |
| KKU8A | Call sign is incorrectly formatted as per FCC Guidelines |
| KKU8Y | Call sign is incorrectly formatted as per FCC Guidelines |
| KKU9C | Call sign is incorrectly formatted as per FCC Guidelines |
| KOKO | Call sign is incorrectly formatted as per FCC Guidelines |
| L4DJF | Call does not fall within a valid group as per FCC Guidelines |
| M4DJF | Call does not fall within a valid group as per FCC Guidelines |
| NB50 | Call sign is incorrectly formatted as per FCC Guidelines |
| NF3NIX | 7. Any 2-by-3 format call sign having the letters NA-NZ as the prefix |
| NU80 | Call sign is incorrectly formatted as per FCC Guidelines |
| O4DJF | Call does not fall within a valid group as per FCC Guidelines |
| P4DJF | Call does not fall within a valid group as per FCC Guidelines |
| PB0RKT | Call does not fall within a valid group as per FCC Guidelines |
| PB8RKT | Call does not fall within a valid group as per FCC Guidelines |
| Q | Call sign is incorrectly formatted as per FCC Guidelines |
| Q4DJF | Call does not fall within a valid group as per FCC Guidelines |
| R4DJF | Call does not fall within a valid group as per FCC Guidelines |
| S4DJF | Call does not fall within a valid group as per FCC Guidelines |
| T4DJF | Call does not fall within a valid group as per FCC Guidelines |
| U4DJF | Call does not fall within a valid group as per FCC Guidelines |
| V4DJF | Call does not fall within a valid group as per FCC Guidelines |
| WA3 ACE | Call sign is incorrectly formatted as per FCC Guidelines |
| WA4 ACE | Call sign is incorrectly formatted as per FCC Guidelines |
| WD2 ACE | Call sign is incorrectly formatted as per FCC Guidelines |
| WD6 ACE | Call sign is incorrectly formatted as per FCC Guidelines |
| WD9 ACE | Call sign is incorrectly formatted as per FCC Guidelines |
| WKRP | Call sign is incorrectly formatted as per FCC Guidelines |
| WR1SKY | 8. Any 2-by-3 format call sign having the letters WC, WK, WM, WR, or WT as the prefix (Group X call signs) |
| Y4DJF | Call does not fall within a valid group as per FCC Guidelines |
| Z4DJF | Call does not fall within a valid group as per FCC Guidelines |