Jamming

Jamming is a sort of radio transmission that is done uniquely with the purpose of interfering in other radio emissions, trying to avoid the listening of these emissions by their listeners. The main motivation for this practice is typically political-ideological.

Jamming was very common during the Cold War. Its use was intense in this period, mainly in the former Soviet Union, that used jamming with great efficiency, inclusively having mounted a special network of jamming stations. The main target of jamming in the Soviet Union were those transmissions realized by the United States and other occidental countries, directed to countries in East Europe (beyond the Iron Curtain) and to Soviet Union. Stations as Voice of America, Radio Liberty and Radio Free Europe were jammed. As these stations tried to scape from jamming emissions, the jammers enhanced their jamming techniques. The operational cost of a jamming station were a lot expensive, when compared with conventional radio stations. Sometimes it was needed to operate a high number of transmitters, or utilize transmitters with high power. Jamming stations achieved pratically the whole spectrum of broadcasting.

With the breakdown of Soviet Union, jamming practice have been reduced. The lower-power stations were closed, specially the ones operating in the Baltic republics (Estonian, Letonia, Lituania). In Russia, several of the jamming stations were selled to privative stations, or are being used as relay stations by occidental stations,

However, jamming is not associated only to the Cold War. Even in this beginning of the 21^st century jamming is still being used. In the present days the main "victims" are emissions directed to Cuba (via Radio Marti), China (via Radio Free Asia), Middle East, among others. For example, in the case of China, the Chinese jamming consists in a endless Chinese instrumental melody, without any announcement, that interfers in pratically every emission to China of Radio Free Asia.

Despite the ones that jam other stations have its own motivations, for the radiolisteners in general that practice can be considered harmful, because it commonly affects stations that are not to be jammed, even these stations that operate in regions far from the areas covered by jamming. In the age of Cold War, the jamming generated in U.S.S.R. had affected also stations in West Europe, or even stations in the American continent. It can be said that jamming represents the "dark side" of the radio broadcasting.