In 1924, the first two call letters “KZ” was assigned to all radio stations in the Philippines in accordance with the laws of the United States of America applicable to the country, which was then an American colony. KZKZ, a 100-watt radio station, replaced the 50-watt radio stations established earlier by Hermann.
In 1929, KZRC, Radio Cebu, opened in Cebu and introduced radio broadcasting in the province. However, it was closed down because shortwave relay signals were unsuccessful between Cebu and Manila. It reopened after a decade and fearlessly went on air with the guerilla movements.
Promulgated in 1931, the Commonwealth Act No. 3840, also known as the Radio Control Law, created the Radio Control Division, the regulatory body of the broadcast industry under the supervision of the secretary of commerce and industry. Later, it was renamed Radio Control Office that lasted until 1972 when President Ferdinand Marcos signed Proclamation No. 1081 and “placed the entire country under martial law” and when the Kapisanan ng mga Brodkasters sa Pilipinas was established “to police its own rank.”
Shortly after the bombing of the Pearl Harbor in Hawaii, Japanese airplanes bombed Manila and attacked Davao, Baguio, Clark Field in Pampanga, and the American Naval Base in Cavite. The Japanese Imperial Army diversionary forces landed in Legaspi, Albay; Aparri, Cagayan; and Vigan, Ilocos Sur and the main invasion forces landed in Lingayen, Pangasinan. President Manuel Quezon, Vice President Sergio Osmeña, and Lt Gen Douglas MacArthur left Manila and departed for Corregidor.
During that time, six commercial radio stations were already established, and these were KZEG, KZIB, KZRC, KZRF, KZRH, and KZRM. Only one of these radio stations, KZRM, stayed on the air for a very long period since 1927.
On December 28, 1941, three weeks after the attack of the Pearl Harbor, the United States provided a shortwave relay station in the Philippines. Radio programs were compiled in Washington, sent out through the NBC network, relayed through the KGEI in San Francisco, California, and beamed to the five radio stations in Manila and to the radio station in Cebu. This long but cumbersome shortwave relay station lasted for six days and was discontinued when the Japanese forces entered and occupied the City of Manila on January 2, 1942 after General MacArthur declared Manila an open city to avoid further destruction and loss of civilian lives. The following day, Gen Masaharu Homma, the Japanese Imperial Army commander in chief, announced the end of the American occupation, the imposition of martial law, and the establishment of the Japanese Military Administration.
As a new alternative, a similar shortwave relay station was provided for a few more days by the navy wireless station but was destroyed when the Japanese forces attack Cavite. When the Filipino and the American troops retreated, all radio stations, except KZRH, were destroyed as part of the “scorched earth policy” of General MacArthur. Subsequently, the Japanese forces reactivated the three radio stations in Manila. These were the better-known KZRH and KZRM, and the lesser-known KZRF. Station KZRH was used by the Japanese Military Administration as its mouthpiece in the country.
Among the three radio stations, two were noted in the United States and in the South Pacific under different call signs. Station KZRH was noted as KAIN, PIAN, and PIRN, while station KZRM was noted as PIAM and PIRM. Obviously, under the Japanese Military Administration, the first two call letters “PI” stood for Philippine Islands.
On February 6, 1942, Gen Emilio Aguinaldo, in a broadcast over the Japanese controlled KZRH, urged General MacArthur to surrender in view of the obvious superiority of Japanese arms contradicting his early pronouncements on June 12, 1941 urging the Filipino people to unite as one in body and soul and cooperate wholeheartedly with the United States if they want to save democracy.
On the other hand, the Far East Broadcasting Company operated two mobile shortwave stations for outside broadcasts. It is likely that one of these stations, probably KZRB, was taken over by the US Army as a temporary shortwave relay station from KGEI in San Francisco, California. KZRB was noted in Australia and in New Zealand as the first shortwave relay station that carried press messages and recorded voice transmissions from the United States mainland to the country
During the Japanese occupation, Filipinos listened to shortwave radio broadcasts from the American forces in Corregidor, Bataan and in Honolulu, Hawaii-an activity that was banned by the Japanese Military Administration. For less than three months, an American radio station with the slogan “Freedom Radio” was aired in Bataan and gave hope and courage to guerilla movements across the archipelago. Filipinos, at that time, depended on radio news broadcast on when the Americans “shall return” as promised by General MacArthur.
When General MacArthur fulfilled his promise and returned in the country with his American troops in Red Beach, Palo, Leyte and when the commonwealth government was reestablished in Tacloban, Leyte on October 20 and 23, 1944, respectively, a temporary shortwave relay station was established in Manila with the call sign KZFM, formerly KZRM before the war and PIAM and PIRM during the war.
