Radio jamming in the context of "Military radio"

Military communications or military signals involve all aspects of communications, or conveyance of information, by armed forces. Examples from Jane's Military Communications include text, audio, facsimile, tactical ground-based communications, naval signalling, terrestrial microwave, tropospheric scatter, satellite communications systems and equipment, surveillance and signal analysis, security, direction finding and jamming. The most urgent purposes are to communicate information to commanders and orders from them.

Military communications span from pre-history to the present. The earliest military communications were delivered by runners. Later, communications progressed to visual signals. For example, Naval ships would use flag signaling to communicate from ship to ship. These flags are a uniform set of easily identifiable nautical codes that would convey visual messages and codes between ships and from ship to shore. Then militaries discovered methods to use audible signaling to communicate with each other. This way of communicating was possible because of telegraphs. They are an electronic device that is used by a sender and when the sender presses on the telegraph key, they interrupt the current creating an audible pulse that is heard at the receiving station. The receiver then decodes the pulses to decode the messages. Since then, military communication has evolved and advanced much further. Today, there are many perspectives used to examine how troops around the world communicate. Anthony King states how Military sociologists have attempted to explain how military institutions develop and maintain high levels of social cohesion. Communication plays a crucial role in fostering social cohesion in the military, as it allows soldiers to build relationships, establish trust, and work together towards common objectives.

Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data. Both human-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science.

EMI can be used intentionally for radio jamming, as in electronic warfare.

Voice of America (VOA or VoA) is an international broadcaster funded by the United States federal government and established in 1942. It is the largest and oldest of the USA's existing international broadcasters, producing digital, TV, and radio content in 48 languages for affiliate stations around the world. Its targeted and primary audience is non-Americans outside the American borders, especially those living in countries without press freedom or independent journalism.

VOA was established in 1942, during World War II. Building on American use of shortwave radio during the war, it initially served as an anti-propaganda tool against Axis misinformation but expanded to include other forms of content like American music programs for cultural diplomacy. During the Cold War, its operations expanded in an effort to fight communism and played a role in the decline of communism in several countries. Throughout its operations, it has aimed to broadcast uncensored information to residents under restrictive regimes, even airing behind the Iron Curtain. In response, some countries began investing in technology to jam VOA broadcasts. In 2017, Russia designated VOA a foreign agent, requiring it to establish a Russian legal entity. It was blocked in Russia along with some other western international broadcasters in 2022. Its programming can be accessed by Russian listeners using VPNs and other software. Its journalists often take substantial risks reporting inside repressive regimes.

In telecommunications, especially radio communication, spread spectrum are techniques by which a signal (e.g., an electrical, electromagnetic, or acoustic) generated with a particular bandwidth is deliberately spread in the frequency domain over a wider frequency band. Spread-spectrum techniques are used for the establishment of secure communications, increasing resistance to natural interference, noise, and jamming, to prevent detection, to limit power flux density (e.g., in satellite downlinks), and to enable multiple-access communications.