Electronic countermeasure

An electronic countermeasure is a technique or device that disrupts, deceives, or evades an opponent’s use of electromagnetic signals, especially radar and communications.

Radar jamming: The transmission of interfering radio-frequency energy to degrade or deny an adversary’s radar detection. It overwhelms or masks radar echoes, directly disrupting an opponent’s sensing.
Electromagnetic spectrum: The complete range of electromagnetic radiation, arranged by frequency or wavelength. Countermeasures exploit or protect portions of this shared operating environment.
Electronic warfare: Military action using the electromagnetic spectrum to sense, protect, attack, or support operations. Electronic countermeasures form the attack and protection techniques within this broader activity.
Battle of Britain: The 1940 air campaign in which Britain defended against German attacks during the Second World War. Its radar defenses made electromagnetic sensing a central target for wartime deception and interference.
Radar deception: The manipulation of radar returns to create false or misleading information about a target. False targets and altered range or velocity exploit radar processing rather than merely overpowering it.
Radar: A system that detects objects by transmitting radio waves and analyzing returned signals. Radar is a principal sensing system that electronic countermeasures seek to disrupt or evade.
Chaff: Small conductive strips dispersed to create radar reflections and confuse tracking systems. Aircraft and ships use it to generate misleading radar returns or obscure a target.
Window (radar countermeasure): A British Second World War radar countermeasure that dispersed strips of metal foil to create false echoes. Its deployment demonstrated how simple materials could confuse radar detection.
Communications jamming: The deliberate interference with radio communications to prevent or degrade message exchange. It applies the same denial principle to an opponent’s communications links.
Radio frequency: The portion of the electromagnetic spectrum used for radio transmission, including radar and communications. Most electronic countermeasures act on signals carried at radio frequencies.

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