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.

  1. KA2AA-KA9ZZ, KC4AAA-KC4AAF, KC4USA-KC4USZ, KG4AA-KG4ZZ, KC6AA-KC6ZZ, KL9KAA- KL9KHZ, KX6AA-KX6ZZ;
  2. Any call sign having the letters SOS or QRA-QUZ as the suffix;
  3. Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU);
  4. Any 2-by-3 format call sign having the letter X as the first letter of the suffix;
  5. 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);
  6. Any 2-by-3 format call sign having the letters AA-AL as the prefix;
  7. Any 2-by-3 format call sign having the letters NA-NZ as the prefix;
  8. Any 2-by-3 format call sign having the letters WC, WK, WM, WR, or WT as the prefix (Group X call signs);
  9. 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;
  10. 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;
  11. 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;
  12. 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 SignRule 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
 A3GEVCall does not fall within a valid group as per FCC Guidelines
 A4DHKCall does not fall within a valid group as per FCC Guidelines
 A4DJFCall does not fall within a valid group as per FCC Guidelines
 A4DK Call does not fall within a valid group as per FCC Guidelines
 A5JLSCall 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
 B4DJFCall does not fall within a valid group as per FCC Guidelines
 C4DJFCall does not fall within a valid group as per FCC Guidelines
COCOCall sign is incorrectly formatted as per FCC Guidelines
 D4DJFCall does not fall within a valid group as per FCC Guidelines
 E4DJFCall does not fall within a valid group as per FCC Guidelines
 F4DJFCall does not fall within a valid group as per FCC Guidelines
 G4DJFCall does not fall within a valid group as per FCC Guidelines
 G7FWBCall does not fall within a valid group as per FCC Guidelines
 G7FWDCall does not fall within a valid group as per FCC Guidelines
 G7FWKCall does not fall within a valid group as per FCC Guidelines
 G7FWTCall does not fall within a valid group as per FCC Guidelines
 G7FWVCall does not fall within a valid group as per FCC Guidelines
 H4DJFCall does not fall within a valid group as per FCC Guidelines
 I4DJFCall does not fall within a valid group as per FCC Guidelines
 J4DJFCall does not fall within a valid group as per FCC Guidelines
K5GRIMCall sign is incorrectly formatted as per FCC Guidelines
K7IDARECall sign is incorrectly formatted as per FCC Guidelines
KCI8UCall sign is incorrectly formatted as per FCC Guidelines
KCI8YCall sign is incorrectly formatted as per FCC Guidelines
KKI8BCall sign is incorrectly formatted as per FCC Guidelines
KKI8CCall sign is incorrectly formatted as per FCC Guidelines
KKI8UCall sign is incorrectly formatted as per FCC Guidelines
KKI8YCall sign is incorrectly formatted as per FCC Guidelines
KKU8ACall sign is incorrectly formatted as per FCC Guidelines
KKU8YCall sign is incorrectly formatted as per FCC Guidelines
KKU9CCall sign is incorrectly formatted as per FCC Guidelines
KOKOCall sign is incorrectly formatted as per FCC Guidelines
 L4DJFCall does not fall within a valid group as per FCC Guidelines
 M4DJFCall does not fall within a valid group as per FCC Guidelines
NB50Call sign is incorrectly formatted as per FCC Guidelines
NF3NIX7.  Any 2-by-3 format call sign having the letters NA-NZ as the prefix
NU80Call sign is incorrectly formatted as per FCC Guidelines
 O4DJFCall does not fall within a valid group as per FCC Guidelines
 P4DJFCall does not fall within a valid group as per FCC Guidelines
PB0RKTCall does not fall within a valid group as per FCC Guidelines
PB8RKTCall does not fall within a valid group as per FCC Guidelines
QCall sign is incorrectly formatted as per FCC Guidelines
 Q4DJFCall does not fall within a valid group as per FCC Guidelines
 R4DJFCall does not fall within a valid group as per FCC Guidelines
 S4DJFCall does not fall within a valid group as per FCC Guidelines
 T4DJFCall does not fall within a valid group as per FCC Guidelines
 U4DJFCall does not fall within a valid group as per FCC Guidelines
 V4DJFCall does not fall within a valid group as per FCC Guidelines
WA3 ACECall sign is incorrectly formatted as per FCC Guidelines
WA4 ACECall sign is incorrectly formatted as per FCC Guidelines
WD2 ACECall sign is incorrectly formatted as per FCC Guidelines
WD6 ACECall sign is incorrectly formatted as per FCC Guidelines
WD9 ACECall sign is incorrectly formatted as per FCC Guidelines
WKRPCall sign is incorrectly formatted as per FCC Guidelines
WR1SKY8.  Any 2-by-3 format call sign having the letters WC, WK, WM, WR, or WT as the prefix (Group X call signs)
 Y4DJFCall does not fall within a valid group as per FCC Guidelines
 Z4DJFCall does not fall within a valid group as per FCC Guidelines