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"Wavescan" is a weekly program for long distance radio hobbyists produced by Dr. Adrian M. Peterson, Coordinator of International Relations for Adventist World Radio. AWR carries the program over many of its stations (including shortwave). Adrian Peterson is a highly regarded DXer and radio historian, and often includes features on radio history in his program. We are reproducing those features below, with Dr. Peterson's permission and assistance.

Wavescan, April 4, 2010

Early Shortwave stations in the Philippines - The RCA Story

Thus far here in Wavescan, we have presented two programs on the radio story in the Philippines; their early Morse Code wireless stations and their early mediumwave stations. In our program today, we continue in the Philippine story with this information about their earliest shortwave station. We go back to the very beginning, in the year 1924.

It was back at this stage that RCA, the Radio Corporation of America, established a regional office in the Philippine capital, Manila. Two years later, work commenced on the construction of the first shortwave radio station in the Philippines at a location nine miles out from Manila. According to a contemporary article in Time magazine, this large new radio station was established by RCP, the Radio Corporation of the Philippines, which was a subsidiary of RCA, the Radio Corporation of America.

According to the article in Time magazine, this new radio station in the Philippines was one of the largest stations in the Far East, and it was constructed specifically for communication with San Francisco in California. At that stage, the RCA communication station at San Francisco was in reality their large station located near Bolinas, a little north of San Francisco.

During the following year, 1927, the usage of four radio transmitters began, two on mediumwave and two on shortwave. The twin mediumwave transmitters, rated at 1 kW each, were inaugurated under the callsign KZRM with a programming service from the city studios on February 12, 1927. The first two letters in the callsign, KZ, indicated the Philippines; and the two final letters, RM, indicated Radio Manila. Quite simultaneously, the RCA communication circuit to Bolinas, California was also inaugurated.

Three years later, it was during the month of May actually, in the year 1930, test broadcasts from RCA Manila were noted on shortwave in the United States and Australia under the experimental callsign K1XR. Programming was a relay from the mediumwave station KZRM and these test broadcasts continued spasmodically for a period of some six months. Then it was that this new shortwave service was officially inaugurated on November 26 under the callsigns KBK and KAZ.

The official opening ceremony for the new international radio telephone service was broadcast on mediumwave KZRM, and also on shortwave as an off-air pick-up in Bolinas California for relay nationwide throughout the United States on mediumwave.

Exactly one month later, a Christmas broadcast was relayed from KZRM back to the United States on two shortwave channels, KAZ on 9900 kHz and KBK on 18750 kHz. Over the following months, many other notable program broadcasts from KZRM Manila were relayed by RCA shortwave and they were heard in the United States and in the South Pacific.

Nevertheless, in spite of the success and the popularity of these shortwave relay broadcasts from Manila, they came to an end in the middle of the following year, 1931. By this stage, the experimental callsign K1XR had been modified according to the new international designation, as KA1XR.

However, this shortwave broadcast service was re-introduced three years later in the same style, with programming from the mediumwave studios of KZRM and the shortwave relay via one or two of the RCA communication transmitters.

Beginning in the year 1937, shortwave station KZRM was heard with a regular relay service from the mediumwave station KZRM, and the evidence would suggest that their 1 kW shortwave transmitter was installed at this stage specifically as a dedicated shortwave relay unit. This transmitter was noted over a period of time on four different shortwave channels, and sometimes carrying the programming from other stations in Manila, including KZEG and KZRF.

During the 1930s and into the early 1940s, RCA Manila was heard on many occasions with a relay of programming from various sources, for example:

During the twelve year era stretching from 1930 into 1941, RCA Manila was noted on the air under at least thirty different callsigns. All of these callsigns began with the letters KA, KB, KT, KU or KZ. It is possible that each twin letter indicated the actual transmitter, and the third letter in each callsign indicated the actual frequency in use.

If this is the case, then we could presume that RCA Manila was on the air with the usage of five different shortwave transmitters. It is known that the RCA communication station near Manila was operating several shortwave transmitters during this era rated at 10 kW, 20 kW and 40 kW.

The usage of RCA Manila during this pre-war era was threefold, as was the custom back in those days:

1. Communication traffic with many Pacific Rim countries
2. The relay of special program broadcasts to and from Pacific Rim countries
3. The broadcast of specific programming for direct reception by shortwave listeners

Even though Radio Manila, RCA, played an important role in the Pacific, Asian and American radio scene back in those days, yet there are no known QSLs verifying the reception of their shortwave programming.