Author: Alan, 5B4AHJ

Callsigns of the format KA#xx can cause some confusion regarding which DXCC entity they are used from.

In the above format # is a numeric digit [0:9] and xx is two consecutive alpha characters [A:Z]

Confusion arises because two separate licensing authorities issued these calls, with an overlapping period when callsigns issued by both authorities were in use at the same time.

In the post-war period in the Pacific, many US service personnel, who were amateur radio operators, were stationed in Japan and the Philippines and were issued with KA#xx callsigns. Stations in Japan, Okinawa, Ogasawara and Minami Torishima using these callsigns were known as Auxilliary Military Radio Stations (AMRS), not to be confused with the Austrian Military Radio Society, also AMRS. AMRS stations were regulated by the Far East Auxiliary Radio League (FEARL), a military organisation.

Although the KA1 prefix was not allocated to AMRS it was used from Iwo Jima (KA1IJ, KA1IW) and Minami Torishima (KA1AA, KA1BL, KA1CG, KA1DX, KA1MC, KA1MI, KA1NC).

From March 1978, FCC started issuing KA#xx callsigns to radio amateurs in the USA, thus overlapping the use of KA#xx callsigns in Japan. 

The first KA#xx calls issued by the FCC were the KA1xx series, commencing in March 1978. These were later followed by KA0xx.

The table below shows how Club Log maps KA#xx callsigns:

ADIF NameADIF DXCC NoDXCC statusDatePrefix
Philippines375Current1946-48KA[1-9] (also three-letter suffixes)
Ogasawara192 Current 1950-59 KA0
Ogasawara192CurrentFrom 1968-06-27 until 1978-03-23KA1
Minami Torishima177CurrentBy exceptionKA1
United States of America291CurrentFrom 1978-03-24KA[0-9]  (also three-letter suffixes)
Japan339CurrentFrom 1950-06-01 until 1978-03-23KA[2-6, 7-9] 
Okinawa193DeletedFrom 1950-06-01 until 1972-05-15KR6 (not KA6)


  • KA#xx calls that do not conform to the above rules are handled by exceptions (eg calls from Japan after 1978-03-23).

References and acknowledgments

AD1C Jim Reisert

JJ1WTL site on the history of Japanese callsigns: JJ1WTL callsign.

K1ZZ David Sumner

W7WLL Don Tucker