 DZRB is the first radio station in the Philippines before the launch of DZRH.On May 8, 1933, the United States-sponsored Insular Government established and operated radio station KZSO in the Philippines on the frequency of 710 kilohertz with a power of 10,000 watts through the United States Information Service.In 1944, the callsign was change to KZFM, named after Frederick Marquardt.