Radio Interference, Industrial

electromagnetic disturbances produced unintentionally during the operation of various electric and radio devices, instruments, and apparatus. Such disturbances act upon the circuits of radio receivers and interfere with radio reception. Sources of industrial radio interference include electric motors in transport vehicles (electric locomotives, streetcars, trolleybuses, and other vehicles) and in household appliances (vacuum cleaners, floor polishers, electric razors, and other appliances), electric communication apparatus (telephone and telegraph equipment), ignition systems for internal-combustion engines (in automobiles and motorcycles), high-voltage electric-power transmission lines, radio receivers and television sets, and high-frequency industrial, medical, and scientific apparatus.

The occurrence of industrial radio interference may be associated with an abrupt change in current or voltage in electric circuits during switching, with static discharges among individual parts of equipment operating at differing voltage levels, or with radio-frequency radiation that is not allocated by radio-communication regulations. Industrial radio interference can reach sensitive components of radio and electronic apparatus through the power-supply system or through an antenna, thus interfering with the normal operation of the apparatus. The interference may cause distortion of information being received, or it may result in a complete loss of information. Thus, for example, industrial radio interference affects the reception of radio and television broadcasts in large cities, where the level of interference is particularly high. The intensity of industrial radio interference at frequencies from 1 megahertz to 1 gigahertz is higher than the intensity of atmospheric, solar, and cosmic interference.

Principal measures aimed at eliminating industrial radio interference consist in the installation of interference-suppressing capacitors, reactors, and electric filters in the power-supply circuits of interference sources and in the effective shielding of such sources. The prevention of industrial radio interference is mandatory in most countries. Measures aimed at preventing industrial radio interference are coordinated by the Comité Internationale Spécial des Perturbations Radioélectriques (CISPR). In the USSR, all enterprises that manufacture or operate devices, instruments, or apparatus that are sources of industrial radio interference are required to take measures to reduce the interference to a level that does not exceed the standards established by the State Commission on Radio Frequencies of the USSR.