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Radar angels are an effect seen on radar displays when there is a periodic structure in the view of the radar that is roughly the same length as the signal's wavelength. The angel appears to be a physically huge object on the display, often miles across, that can obscure real targets. These were first noticed in the 1940s and were a topic of considerable study in the 1950s. The underlying mechanism is due to Bragg's law.

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  • Ange radar (fr)
  • Radar angels (en)
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  • Les anges radar (ou écho-mirage) sont des échos radar qui ne peuvent être attribués à des réflexions sur des cibles liquides ou solides, mais à des variations de l'indice de réfraction de l'air. Ce phénomène est comparable à l'effet miroir que l’on peut noter lorsqu’on regarde à travers un certain nombre de verres. À l'interface entre le milieu optiquement plus dense (verre) et le milieu optiquement mince (air), le rayon lumineux est en partie réfléchi. On voit donc une réflexion bien qu’il n’y ait pas de miroir à proprement parler. Le mécanisme sous-jacent est dû à la diffusion de Bragg. (fr)
  • Radar angels are an effect seen on radar displays when there is a periodic structure in the view of the radar that is roughly the same length as the signal's wavelength. The angel appears to be a physically huge object on the display, often miles across, that can obscure real targets. These were first noticed in the 1940s and were a topic of considerable study in the 1950s. The underlying mechanism is due to Bragg's law. (en)
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  • http://commons.wikimedia.org/wiki/Special:FilePath/S_band_angel_1959.png
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  • Les anges radar (ou écho-mirage) sont des échos radar qui ne peuvent être attribués à des réflexions sur des cibles liquides ou solides, mais à des variations de l'indice de réfraction de l'air. Ce phénomène est comparable à l'effet miroir que l’on peut noter lorsqu’on regarde à travers un certain nombre de verres. À l'interface entre le milieu optiquement plus dense (verre) et le milieu optiquement mince (air), le rayon lumineux est en partie réfléchi. On voit donc une réflexion bien qu’il n’y ait pas de miroir à proprement parler. Le mécanisme sous-jacent est dû à la diffusion de Bragg. (fr)
  • Radar angels are an effect seen on radar displays when there is a periodic structure in the view of the radar that is roughly the same length as the signal's wavelength. The angel appears to be a physically huge object on the display, often miles across, that can obscure real targets. These were first noticed in the 1940s and were a topic of considerable study in the 1950s. The underlying mechanism is due to Bragg's law. (en)
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