“radio window”的概念、定义、翻译、参考文献-科学参考

radio window

Physics

A region of the electromagnetic spectrum in the radio-frequency band within which radio waves can be transmitted through the earth’s atmosphere without significant reflection or attenuation by constituents of the atmosphere. It extends from about 10 megahertz to 100 gigahertz and enables radiation in this range from celestial radio sources to be picked up by radio telescopes on the earth’s surface. Below 100 MHz incoming radio waves are reflected by the ionosphere and those above 100 GHz are increasingly affected by molecular absorption.

Astronomy

A region of the electromagnetic spectrum in which the Earth’s atmosphere is relatively transparent to radio waves. It extends over a wavelength range of approximately 1 cm to 30 m. At the short-wave end of the window, radio waves are blocked by water vapour, and at the long-wave end by the Earth’s ionosphere. Most of the radio spectrum is occupied by broadcasting and telecommunications services and only a few narrow bands are kept free for radio astronomy, notably those coinciding with the position of important spectral lines, such as the 21-cm hydrogen line at 1420 MHz.

Electronics and Electrical Engineering

The range of radiofrequencies that are not reflected by the ionosphere but pass straight through it. The radio window extends from about 300 gigahertz to about 15 megahertz (approximate wavelength range: 1 mm to 20 m). The effect of the ionosphere is still noticeable up to 100 MHz but decreases as the radiofrequency is increased. At frequencies above 10 GHz heavy rain can severely affect transmission.
High-frequency television broadcasts fall within the radio window and long-distance television communication therefore requires the use of communications satellites as reflectors. Radio astronomy is also restricted to this frequency range.

单词	radio window
释义	radio window Physics A region of the electromagnetic spectrum in the radio-frequency band within which radio waves can be transmitted through the earth’s atmosphere without significant reflection or attenuation by constituents of the atmosphere. It extends from about 10 megahertz to 100 gigahertz and enables radiation in this range from celestial radio sources to be picked up by radio telescopes on the earth’s surface. Below 100 MHz incoming radio waves are reflected by the ionosphere and those above 100 GHz are increasingly affected by molecular absorption. Astronomy A region of the electromagnetic spectrum in which the Earth’s atmosphere is relatively transparent to radio waves. It extends over a wavelength range of approximately 1 cm to 30 m. At the short-wave end of the window, radio waves are blocked by water vapour, and at the long-wave end by the Earth’s ionosphere. Most of the radio spectrum is occupied by broadcasting and telecommunications services and only a few narrow bands are kept free for radio astronomy, notably those coinciding with the position of important spectral lines, such as the 21-cm hydrogen line at 1420 MHz. Electronics and Electrical Engineering The range of radiofrequencies that are not reflected by the ionosphere but pass straight through it. The radio window extends from about 300 gigahertz to about 15 megahertz (approximate wavelength range: 1 mm to 20 m). The effect of the ionosphere is still noticeable up to 100 MHz but decreases as the radiofrequency is increased. At frequencies above 10 GHz heavy rain can severely affect transmission. High-frequency television broadcasts fall within the radio window and long-distance television communication therefore requires the use of communications satellites as reflectors. Radio astronomy is also restricted to this frequency range.
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