"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 N426, April 23, 2017
Focus on the Middle Americas: El Salvador on Shortwave
An unidentified amateur radio operator in San Salvador, the capital city of the small Central American country of El Salvador, was the first to enter into experimentation with shortwave radio. He sent a written report of his early activities to the American amateur radio magazine QST, and they printed his remarks in their issue dated December 1922. He said that he had recently made some successful shortwave tests from his own radio transmitter, and that he planned on making further test transmissions on shortwave sometime soon.
Back in the year 1922, the emphasis in the radio world was the usage of high power on longwave rather than low power on shortwave, and at that time shortwave experimentation was quite rare. The amateur radio experimenter in San Salvador identified himself simply as Sparks, seeming to indicate that he was an unlicensed amateur radio operator, which was rather common in many countries back in that era.
Many international radio monitors in the United States and the South Pacific made frequent comment in the mid and late 1930s regarding shortwave transmissions from El Salvador. It would appear that new shortwave equipment was installed in San Salvador around the year 1935, apparently at an already established radio communication station somewhere in the capital city area.
Mention of new low powered shortwave transmissions from El Salvador soon began to appear in radio magazines in the United States and Australia, and the first known reference (Australasian Radio World, August 1936) listed the station as the new YSJ which was heard in Australia on 13410 kHz. Apparently this entry was for the logging of a communication transmission, rather than for the broadcast of entertainment radio programming.
However, during the following year (1937), monitoring reports in radio magazines referred to the fact that the new 500 watt transmitter in San Salvador was now in use at various times of the day with the relay of programming from mediumwave Radio Nacionales YSS (864 kHz). The Listener In radio magazine in Australia referred to the new shortwave broadcasts as a new shortwave station in a new shortwave country.
According to propagation conditions, three channels and three callsigns were employed for the relay of entertainment and informational radio programming: YSD 7894 kHz, YSH 9520 kHz, YSM 11710 kHz. However, it should be noted that only one channel was on the air at any one time, seeming to indicate the usage of just the one transmitter.
Somewhere around the middle of last century, a new 1 kW transmitter was installed for the shortwave service of Radio Nacionales. Then some ten years later again, another 5 kW transmitter was in use for the program relays; and in the mid-1980s, YSS shortwave was noted with a power of 10 kW. However, soon after this increase in power, the government shortwave service came to an end.
It should be noted also that there were many other double combination mediumwave/shortwave stations on the air in El Salvador, with a maximum number of 18 around the mid-1950s, all commercial. The final listing for a shortwave broadcasting station in El Salvador was for Radio Imperial with 1.5 kW under the callsign YSDA about a dozen years ago.
El Salvador is geographically a small country, and shortwave transmissions were not really necessary to ensure nationwide coverage. Then too, the introduction of FM broadcasting began to supersede the usage of both shortwave and mediumwave for nationwide coverage.
In a rather strange situation, two major clandestine shortwave stations in El Salvador were on the air surreptitiously for many years, though more recently the government has granted a license to each, and both are on the air in the capital city, though on FM only. Those clandestine shortwave events transpired during the disastrous and tragic civil war in El Salvador that extended over a period of eleven years, stretching from 1981 to 1992.
On January 10, 1981, Radio Venceremos made its first broadcast in El Salvador from a damp cave in an isolated hidden mountainous area of the country, though it is claimed that they were previously on the air from a clandestine location in Nicaragua. Much of the programming from Radio Venceremos was pre-recorded on cassette tapes and then broadcast over whatever shortwave equipment was available.
Daily one hour programming began at 6:00 pm local, and the contents featured news and information about the civil war that was not readily available from any other source. The daily news and wartime features from this forbidden radio station were listened to avidly not only by the citizens of this war torn country, but also by the news media and high level politicians in other countries.
The original old transmitter, identified in some circles as a Viking, together with a 700 watt amplifier, carried the broadcasts of Radio Venceremos during its first era. Other electronic equipment was pressed into service whenever and wherever it could be obtained, and of course, frequent moves were necessary to obviate capture or destruction. When the operation became more professional, two transmitters were employed with simultaneous programming on nearby channels.
Radio Venceremos usually transmitted somewhere around the 40 metre amateur band, and the actual frequency hopping varied in order to avoid jamming. There were times also when the jamming transmitter would come on the air with its own programming immediately after Radio Venceremos closed, on the same channel.
Radio Venceremos: 1981 Identification announcement
In an endeavor to counter the broadcasts from Radio Venceremos, the United States stationed two navy ships in the Caribbean off the coast of Central America. These two navy vessels were Spruance class destroyers, and they were located in the Gulf of Fonseca.
Programming from the shortwave communication transmitters on these two vessels, first the "Caron" and later the "Diego," consisted entirely of jamming noises. The signal from these two ships was also heard widely throughout North America and into Europe and the South Pacific. It could be conjectured that no QSLs were ever issued for these jamming broadcasts.
After peace talks produced some sort of a peace keeping truce, Radio Venceremos was granted an FM license, and some of its early equipment can be seen these days as a rebuilt display in the city museum.
The story of the other clandestine radio station in El Salvador, Radio Farabundo Marti, is quite similar to that of Radio Venceremos. Radio Farabundo Marti made its first broadcast on January 22, 1982; and this station is now also licensed as an FM station in San Salvador. Just a few QSLs are known for Venceremos and Farabundo Marti and these are informal cards and notes. However, in earlier days, QSL cards were issued by Radio Nacionales YSS for the reception of their shortwave broadcasts.