Author: Alan, 5B4AHJ

Prefixes of U.S. administered callsigns prior to WWII were very different to those in the post-WWII period.

However, the pre-WWII prefixes continued to be used for a short time after the end of WWII, and thus are of interest for Club Log.

As far as I can ascertain, new prefixes began to be issued in early 1946, and the changeover was largely complete before the end of 1946.

Known prefixes (this may not be a complete list), including Club Log mapping dates - log in to Club Log to view QSLs (not necessary for K8CX QSLs):

Old prefix
Mapped until QSL  New prefix Mapped from  QSL  DXCC Entity
Notes & acknowledgements
K4 1946-12-31 W3HUN/K4
KP4 1945-11-15 KP4AU
Puerto Rico
K5 Not QRV post WWII
N/A KZ5  1945-11-15
Canal Zone  Tnx W2VRK
K6 1946-12-31 W1MVF/K6
KH6 1946-07-01 KH6CN
Hawaii Tnx Patrick Rigg, K8CX
K7 1946-12-31 W6QJW/K7
KL7 1945-11-15 KL7AD
Alaska Tnx Patrick Rigg
K4, KB4 May not have been QRV post WWII
N/A KV4 1945-11-15
US Virgin Islands Tnx W2VRK, F5VHY
KB6 1946-06-30 W2LRI/KB6 
KG6 1946-07-01
Mariana Islands, Guam  Tnx G4UZN, K8CX
KC6 Not mapped QSL required KW6 1945-11-15 W6VDG/KW6
Wake Island Tnx Patrick Rigg.
KD4 Not QRV post WWII
KS4 1945-11-15
Swan Island  Tnx K8CX
KD6 1946-12-31  QSL required
KM6 1945-11-15
Midway Island Tnx K8CX
KE6 1946-12-31
KJ6  1945-11-15
Johnston Island  Tnx W2VRK, Patrick Rigg


KB6  1946-07-01 KB6AD
Baker, Howland and American Phoenix Islands Tnx Patrick Rigg, K8CX
Tnx Patrick Rigg

 KC6 may not have been used pre-WWII

KG6 1946-06-30
QSL required
KP6 1945-11-15  KP6AB
Jarvis & Palmyra Island Tnx Patrick Rigg
KH6 1946-06-30  QSL required
KS6 1945-11-15  W0OZW/KS6
American Samoa W3LJL/KH6 QRV 1946. Tnx XTAL Magazine Vol 7, #8, October, 1946,  K8CX
NY1, NY2 Not QRV post WWII
N/A KZ5 See above
See above Canal Zone 
NY4 1949-12-31 NY4DD
KG4 1949-01-01 KG4AD
Guantanamo Bay Tnx  G4UZN. NY4DD  became KG4AD sometime in the period 1949-03-26 to 1949-07-02

The following is an extract from QST April, 1946:

The following is an extract from QST February, 1947:


The only prefixes for USA prior to 1947 were W[1-9], there was no W0 prefix.


ARRL/QST April, 1946

Stephen Emlyn-Jones, GW4BKG

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