Radio Wave Spectrum, mobile communication, the propagation, frequency resources, diffraction capability, communication system, coverage distance. A radio programme receiver does not need to be directly in viewof the transmitter to receive programme signals. For low frequencyradio waves diffraction can allow them to be received behind hills. ., diffraction, and absorption is of critical importance in the study of how radio waves move in free space and over the surface of the Earth.
English-Russian marine dictionary . 2014.
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refraction — refractional, adj. /ri frak sheuhn/, n. 1. Physics. the change of direction of a ray of light, sound, heat, or the like, in passing obliquely from one medium into another in which its wave velocity is different. 2. Ophthalm. a. the ability of the … Universalium
refraction — the tendency for waves to become more parallel to the coastline as they approach it. Caused by the slowing of waves at their base as they enter shallower water … Geography glossary
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GRIB — RUSSIA (see also List of Individuals) 17.9.1912/RU 6.11.1978 Leningrad/RU Anatoly Andreevich Grib graduated in 1934 from the Saint Petersburg State University. He then moved to the Tomsk State University where he presented his PhD thesis in the… … Hydraulicians in Europe 1800-2000
light — light1 lightful, adj. lightfully, adv. /luyt/, n., adj., lighter, lightest, v., lighted or lit, lighting. n. 1. something that makes things visible or affords illumination: All colors depend on light. 2. Physics … Universalium
radiation — radiational, adj. /ray dee ay sheuhn/, n. 1. Physics. a. the process in which energy is emitted as particles or waves. b. the complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and… … Universalium
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Diffraction is when waves bend around the corner of an obstacle.
It is most easily seen when a wave spreads out after passing through a gap.
Medium gap: some diffraction, but mostly straight
Wavelength-size gap: most diffraction
The maximum effect is when the gap and wavelength are similar in size.
Here we see diffraction as waves enter a harbor:
Diffraction is very important for Radio Waves: it lets them get around hills and into valleys:
Radio waves with wavelengths of kilometers diffract
over hills and through valleys so you can easily get reception.
But microwaves with wavelength of centimeters tend to go straight.