In 1973 (due to Martial Law), the 1000 khz frequency which is used by ABS-CBN at that time under the callsign DZMM, was given to GMA and the callsign was changed to DZXX. In 1975, it changed its call letters to DWXX (Double X) 1000 kHz (later moved to 1026 kHz in 1978) and it was then a sister station of DZBB 580 kHz (now 594 kHz), featuring a pop music format. Later on, Hypersonic Broadcasting Center acquired the station from the Republic Broadcasting System (now GMA Network) while DWXX 1026 finally closed shop on April 15, 1987. On May 10, 1987, when Nation Broadcasting Corporation took over the 1026 AM frequency, it was rebranded as DZAM Radyo 1026: Ating Maaasahan, which would also rebrand later as DZAM Radyo Commando. During that period, the station operated with 10 kW output, and it featured a uniform network type format (a.k.a. TV-on-radio format), consisting of news, and well-balanced mix of talk, music and entertainment programming for listeners of all ages; as well as live coverage of PBA games at that time.