Radio frequency interference

Radio frequency interference is unwanted radio-frequency energy that contaminates signals being measured or received. It can arise from human-made transmitters and electronics or from natural sources.

Radio astronomy: The study of celestial objects and phenomena through their radio emissions. Radio astronomy measures faint cosmic emissions that terrestrial transmissions can readily mask.
Radio frequency interference mitigation: Methods for detecting, suppressing, or avoiding unwanted radio signals in measurements and communications. It collects the practical techniques used to protect radio observations.
Radio transmitter: A device that generates and radiates electromagnetic signals at radio frequencies. Broadcast and communications transmitters are major human-made sources of contamination.
Thermal noise: Random electrical fluctuations produced by the thermal motion of charged particles. Thermal noise is intrinsic and broadly random, unlike identifiable external interference.
Radio receiver: An electronic system that selects and processes radio-frequency signals. Its antennas and circuitry are common entry points for unwanted signals.
Radio quiet zone: A regulated area where radio transmissions are restricted to protect sensitive instruments. Such zones limit local interference near major observatories.
Wireless networking: Communication between devices using radio waves rather than wired links. Wi-Fi and other wireless systems can leak energy into astronomical measurements.
Cosmic microwave background: Relic electromagnetic radiation from the early universe, observed mainly at microwave frequencies. It is a genuine cosmic signal, not contamination, despite occupying similar frequencies.
Electromagnetic compatibility: The ability of electrical equipment to operate without causing or suffering unacceptable electromagnetic interference. Its engineering practices reduce emissions and susceptibility in observing instruments.
Green Bank Observatory: A U.S. radio astronomy observatory in West Virginia, within the National Radio Quiet Zone. Its protected location and operating rules address interference directly.

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