Back just before the middle of last century, the government licensing authority in the United States issued a decree stating that every shortwave transmitter should be licensed under its own separate callsign. How simple it would be in researching the history of international radio broadcasting if every shortwave station in every country around the world was identified in this way. But that has not been the case.
In earlier times in the United States for example, a list of shortwave channels for the RCA station located at Bolinas in California was published in the monthly magazine, Radio News, for August 1935. This list shows almost thirty different three letter callsigns ranging from KEB to KWE; one callsign per channel, not one callsign per transmitter. There were occasions when a couple of these transmitters were in use for the relay of broadcast programming to Hawaii and across the Pacific.
This same 1935 list shows more than twenty callsigns for the large RCA terminal on the east coast, at Rocky Point on Long Island, New York. These three letter callsigns run from WAJ down through WQP, though not all of these letters were taken up by this station.
Interestingly, when this RCA station at Rocky Point was on the air with radio broadcast programming, an experimental callsign, W2XBJ was in use, regardless of transmitter and regardless of frequency.
However, it is true; most of the shortwave stations in the United States that were on the air with broadcast programming during the 1930s & 1940s were identified with just one callsign per transmitter. Examples of this form of callsign usage would be:-
W8XK Pittsburgh Pennsylvania
WRUW & WRUL Scituate Massachusetts
KGEI & KGEX Belmont California
W4XB Miami Beach Florida
W2XAD & W2XAF Schenectady New York
Going northwards into Canada for example, one authority informs us that the basic callsign for the large shortwave station located at Sackville, New Brunswick is CKCX. However, during the earlier part of its history, this shortwave station was on the air with one callsign per each shortwave channel. These callsigns were made up with four letters in the English alphabet, all beginning with CH or CK. The basic callsign, CKCX, identified both the station, and also the shortwave channel 15190 kHz.
At the time, Radio Canada International was on the air with three new shortwave transmitters at 50 kW each, obtained from RCA in the United States.
Over in England during the15 year period extending from 1930 to the mid 1940s, the BBC London was on the air from a total of 46 shortwave transmitters installed at eight different locations scattered throughout different areas in England, and including Northern Ireland. This enormous assemblage of shortwave transmitters ranged in power from 7.5 kW right up to 250 kW.
During this era in the middle of last century, this huge bevy of shortwave transmitters was on the air under various callsigns; not with one callsign per transmitter, but with one callsign per shortwave channel. These callsigns, numbering more than one hundred, ran from GRA to GSZ and GVA to GWZ.
Under these circumstances, the BBC operated with maximum flexibility, and they could use any transmitter, at any location, at any desired power level, on almost any shortwave channel. It was therefore impossible for the international radio monitors in those days to know just which transmitter at which location they were listening to.
Over in Australia, the old AWA shortwave station located at Pennant Hills, an outer suburb of Sydney in New South Wales, was on the air with an interesting mixture of callsigns. For example, they operated three different communication transmitters during the middle of last century, and these shortwave units were identified with the internationally recognized Australian callsigns; VLK, VLM & VLN. However, when AWA Pennant Hills was calling:-
England with communication traffic, they identified with the callsign VLK
New Zealand VLZ.
When Radio Australia was launched at the end of 1939 under the slogan, “Australia Calling”, transmitters VLK & VLM were taken into service with new callsigns, as VLQ & VLQ2. However, this was also somewhat confusing, due to the fact that transmitter VLQ was also on the air under another numeric callsign on another channel, as VLQ5.
In 1939, the 2 kW ABC shortwave transmitter at Lyndhurst in Victoria was in use for both the ABC Home Service as well as Australia Calling. In mid 1941, an additional 10 kW shortwave transmitter was installed at Lyndhurst, and this was inaugurated under the same callsign VLR. However, with the two transmitters at the same location, and both on the air under the same callsign, this became quite confusing. So it was that the callsign of the new transmitter was changed, and it became identified as the more familiar VLG.
In 1946, another 10 kW shortwave transmitter was installed at Lyndhurst, and this one was identified as VLH. However, by this time, the program relays of mediumwave 3AR & 3LO via VLR and VLH were quite regular and consistent for Home Service coverage throughout Australia.
At one stage back then around mid morning, there were two 10 kW transmitters on the air with the VLH service on two different shortwave channels, with overlapping scheduling for a quarter hour or more. Thus, VLH, was by this stage, more a program service on shortwave rather than a transmitter identification.
The Shepparton shortwave station was on the air under Radio Australia with three transmitters that were identified as VLA, VLB & VLC. When these transmitters were given a new shortwave channel, a suffix number was added, such as:-
VLA2 on 9615 kHz and VLA3 on 9680 kHz
VLB3 11770 VLB4 11810
VLC9 17840 VLC10 21680
However, this system became quite cumbersome, so Radio Australia changed the system in mid 1951 and the suffix numeral indicated the MHz band; thus:-
VLA7 Any channel in the 7 MHz 41 metre band
VLB9 9 31
VLC11 11 25
It is true, that the usage of callsigns throughout the world to designate shortwave transmitters is decreasing. However, we would suggest that the best system for the identification of a shortwave transmitter has always been the simplest, and that is; one callsign, one transmitter.
(AWR-Wavescan/NWS # 42 via Adrian Peterson)