On May 15, 1923, the Federal Radio Commission expanded the broadcast band, and WBAP and WFAA moved to 630 kHz. Another expansion moved WBAP to 600 kHz effective April 15, 1927, and this frequency was shared with WOAI in San Antonio. On November 11, 1928, WBAP moved to 800 kHz, and on June 1, 1929, WFAA also moved to 800 kHz, sharing time (and NBC Red network affiliation) with WBAP. Station owner Amon G. Carter was unhappy with having to share time on 800 kHz with WFAA. Carter Publishing purchased KGKO in Wichita Falls (570 kHz) and moved it to Fort Worth as an affiliate of the NBC Blue network (which became ABC), and more importantly as a second frequency to be used when 800 kHz was not available. The sale was approved by the Federal Communications Commission September 24, 1935. On March 29, 1941, as a consequence of the Treaty of Havana, WBAP and WFAA moved one last time, to 820 kHz.