业余爱好者
发表于 2025-3-23 12:27:09
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歌曲
发表于 2025-3-23 16:15:08
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Flatter
发表于 2025-3-23 21:43:32
Propagation of Radio Waves in a Dielectric,From a physical standpoint it is evident that the waves radiated by an antenna propagate in all directions in space, since the wave surfaces are closed. However, at a sufficiently large distance from the source, and when considering only the behaviour of the waves in the vicinity of the receiving antenna, we are dealing with plane waves.
IRS
发表于 2025-3-24 00:08:51
,Wave Propagation Close to the Earth’s Surface,Wave propagation in the atmosphere can be studied by means of simple reasoning, using geometric optics. The determination of the wave planes and the plotting of the radii are both easy. Planes of equal phase are confused with planes of equal amplitude.
同谋
发表于 2025-3-24 03:24:29
Ionospheric Propagation,The propagation of waves in the ionosphere can be studied by the same methods as used for examining the effect of the earth’s surface, where ionosphere is an imperfectly conducting sphere. This is the theory proposed by Eckersley. and more recently by Bremmer., Wait., Budden. and other workers.
COMMA
发表于 2025-3-24 07:27:40
Principles of Calculating a Radio Link,In order to determine whether radio communication is possible and what its quality will be, we must first calculate the field received, then the field required for a communication of the desired type and quality, and finally ensure that the first result is higher than the second.
linear
发表于 2025-3-24 14:45:46
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Substance
发表于 2025-3-24 17:59:23
Philips Technical Libraryhttp://image.papertrans.cn/r/image/820655.jpg
阴郁
发表于 2025-3-24 21:44:31
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finite
发表于 2025-3-25 02:58:30
N. V. Philips Gloeilampenfabrieken, Eindhoven 1974