First station[]
- Date: December 8, 1921-March 23, 1922 ( NOTE: One source states that station ended operations on March 23, 1922; another listing shows this station still in service on May 15, 1922, but also shows the second station on that date. The United States Department of Commerce Radio Service Bulletin[1] dated April 1, 1922 indicates the station had ceased operations, so the March date is probably correct.)
- Frequency:
- 500 khz (...January 3, 1922...) [concurrently with other listed frequencies, see history page]
- 833 khz (December 8, 1921-March 23, 1922) (Assumed to start at beginning, not given in any source for operations prior to January 3, 1922.)
- 1000 khz (...January 3, 1922...) [concurrently with other listed frequencies, see history page]
- Location: San Francisco, California (...January 3, 1922-March 23, 1922)
- Owner of license:
- Edwin L. Lorden (...January 3, 1922-March 23, 1922)
Second station[]
- Date: April 8, 1922-December 11, 1925
- Frequency:
- 833 khz (April 8, 1922-June 30, 1923...)
- 1190 khz (...June 30, 1924...)
- 1200 khz (...March 1925-June 30, 1925...)
- Location:
- Tacoma, Washington (...May 15, 1922-June 30, 1925...)
- Owner of license:
- William A. Mullins Electric Co. (...May 15, 1922-June 30, 1923...)
- Tacoma Daily Ledger (...June 30, 1924-March 1925...)
Third station[]
- Date: March 27, 1928-March 15, 1982
- Previous call letters: KFBC
- Frequency:
- 1210 khz (...June 30, 1928...)
- 1330 kHz (...March 29, 1941)
- 1360 kHz (March 29, 1941...)
- Location:
- San Diego, California (...June 30, 1928-March 15, 1982)
- Owner of license:
- Arthur W. Yale (...June 30, 1928...)
- Subsequent call letters: KCNN
Fourth Station[]
- Date: July 3, 2020