 Apo Science Foundation (MASFI), another institution also owned by Torres and is a sister association to the UM.In November 1978, due to the switch of the Philippine AM dial from the NARBA-mandated 10 kHz spacing to the 9 kHz rule implemented by the Geneva Frequency Plan of 1975, the station's frequency was transferred to 936 kHz.During the 1970s and the 1980s, DXUM was the top music station in Davao City.