Invalid Call Sign Requests

Last updated Sunday, November 8, 2026 10:01:27 AM (Arizona)
Sunday, November 8, 2026 5:01:27 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
 A5MO Call does not fall within a valid group as per FCC Guidelines
AY3MA 3.  Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU)
AY3MY 3.  Any call sign having the letters AM-AZ as the prefix (these prefixes are assigned to other countries by the ITU)
BJ5EJ Call does not fall within a valid group as per FCC Guidelines
IL5LD Call does not fall within a valid group as per FCC Guidelines
IL5RT Call does not fall within a valid group as per FCC Guidelines
JL5BM Call does not fall within a valid group as per FCC Guidelines
K54RJCall sign is incorrectly formatted as per FCC Guidelines
K54RSCall sign is incorrectly formatted as per FCC Guidelines
KJ4STERCall sign is incorrectly formatted as per FCC Guidelines
KSR0Call sign is incorrectly formatted as per FCC Guidelines
KSRACall sign is incorrectly formatted as per FCC Guidelines
KTZ71Call sign is incorrectly formatted as per FCC Guidelines
LC5MD Call does not fall within a valid group as per FCC Guidelines
MA3AAYCall does not fall within a valid group as per FCC Guidelines
MA3ALACall does not fall within a valid group as per FCC Guidelines
MA3AY Call does not fall within a valid group as per FCC Guidelines
MI3KO Call does not fall within a valid group as per FCC Guidelines
MI3YO Call does not fall within a valid group as per FCC Guidelines
N54RSCall sign is incorrectly formatted as per FCC Guidelines
NC4USA7.  Any 2-by-3 format call sign having the letters NA-NZ as the prefix
NSR0Call sign is incorrectly formatted as per FCC Guidelines
NSRACall sign is incorrectly formatted as per FCC Guidelines
WNBJJZCall sign is incorrectly formatted as per FCC Guidelines
WSR0Call sign is incorrectly formatted as per FCC Guidelines
WSRACall sign is incorrectly formatted as per FCC Guidelines
YO3KO Call does not fall within a valid group as per FCC Guidelines
YU3UI Call does not fall within a valid group as per FCC Guidelines
ZEROCall sign is incorrectly formatted as per FCC Guidelines