optical spectrum frequency communications
71Metamaterial antenna — This Z antenna tested at the National Institute of Standards and Technology is smaller than a standard antenna with comparable properties. Its high efficiency is derived from the Z element inside the square that acts as a metamaterial, greatly… …
72Ultraviolet — UV redirects here. For other uses, see UV (disambiguation). UVB redirects here. For the mysterious shortwave radio station in Russia, see UVB 76. For other uses, see Ultraviolet (disambiguation). False color image of the Sun s corona as seen in… …
73Invention of radio — Great Radio Controversy redirects here. For the album by the band Tesla, see The Great Radio Controversy. Contents 1 Physics of wireless signalling 2 Theory of electromagnetism …
74telephone — telephoner, n. /tel euh fohn /, n., v., telephoned, telephoning. n. 1. an apparatus, system, or process for transmission of sound or speech to a distant point, esp. by an electric device. v.t. 2. to speak to or summon (a person) by telephone. 3.… …
75Medium wave — Main article: Medium frequency Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz[1] and in North America an extended MW… …
76Communication with submarines — is difficult because radio waves do not travel well through thick electrical conductors like salt water. The obvious solution is to surface and raise an antenna above the water, then use ordinary radio transmissions. Early submarines had to… …
77Mobile radio — This article is about professional equipment. For mobile radios used in amateur radio, see amateur radio mobile operation. Mobile radio or mobiles refer to wireless communications systems and devices which are based on radio frequencies, and… …
78Global Positioning System — GPS redirects here. For other uses, see GPS (disambiguation). Geodesy Fundamentals …
79National Telecommunications and Information Administration — Agency overview Formed 1978 Jurisdict …
80WiMAX — Worldwide Interoperability for Microwave Access Logo trademarked by the WiMAX Forum …
