sentences:  KMPX (defunct)
  
  KMPX (106.9 FM) was a San Francisco FM radio station which was best known in the late 1960s as the birthplace of America's freeform progressive rock format ("Underground radio") and in the 1970s as the only station nationally devoted to playing big band music full-time.On December 10, 1959, the station, owned by San Francisco businessman Franklin Mieuli, signed on at 106.9 MHz with the KPUP call letters.