transmitting wave
81Ionosphere — The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner …
82Non-line-of-sight propagation — Non line of sight (NLOS) or near line of sight is a term used to describe radio transmission across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone. Many types of radio transmissions depend, to… …
83physical science, principles of — Introduction the procedures and concepts employed by those who study the inorganic world. physical science, like all the natural sciences, is concerned with describing and relating to one another those experiences of the surrounding… …
84Superheterodyne receiver — A 5 tube superheterodyne receiver made in Japan around 1955 In electronics, a superheterodyne receiver (sometimes shortened to superhet) uses frequency mixing or heterodyning to convert a received signal to a fixed intermediate frequency, which… …
85Alternating current — (green curve). The horizontal axis measures time; the vertical, current or voltage. In alternating current (AC, also ac) the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge …
86Crystal radio — Crystal set redirects here. For the Australian rock band, see The Crystal Set. A modern reproduction of an antique crystal set. It is tuned to different stations by moving the sliding contact (right) up and down the tuning coil (red). The device… …
87Anechoic chamber — An anechoic chamber An anechoic chamber (an echoic meaning non echoing or echo free) is a room designed to stop reflections of either sound or electromagnetic waves. They are also insulated from exterior sources of noise. The combination of both… …
88Spark-gap transmitter — A spark gap transmitter is a device for generating radio frequency electromagnetic waves. These devices served as the transmitters for most wireless telegraphy systems for the first three decades of radio (1887 ndash;1916) and the first… …
89Radio Caroline — is a European radio station that started transmissions on Easter Sunday 1964 from a ship anchored in international waters off the coast of Felixstowe, Suffolk, England. [ [http://www.radiocaroline.co.uk/history2.asp Don t Get Mad, Get Even] ] It… …
90Pulmonary contusion — Classification and external resources A CT scan showing a pulmonary contusion (red arrow) accompanied by a rib fracture (blue arrow) ICD 10 S …
