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When a racon receives a radar pulse, it responds with a signal on the same frequency which puts an image on the radar display. This takes the form of a short line of dots and dashes forming a Morse character radiating away from the location of the beacon on the normal plan position indicator radar display. The length of the line usually ...
The air traffic control radar beacon system ( ATCRBS) is a system used in air traffic control (ATC) to enhance surveillance radar monitoring and separation of air traffic. It consists of a rotating ground antenna and transponders in aircraft. The ground antenna sweeps a narrow vertical beam of microwaves around the airspace.
A typical relay service conversation. A telecommunications relay service, also known as TRS, relay service, or IP-relay, or Web-based relay service, is an operator service that allows people who are deaf, hard of hearing, deafblind, or have a speech disorder to place calls to standard telephone users via a keyboard or assistive device.
Worldwide distribution of country calling codes. Regions are coloured by first digit. Country calling codes, country dial-in codes, international subscriber dialing (ISD) codes, or most commonly, telephone country codes are telephone number prefixes for reaching telephone subscribers in foreign countries or areas via international telecommunication networks.
Amateur teleprinting over radio (AMTOR) D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode. Hellschreiber, also referred to as either Feld-Hell, or Hell a facsimile-based teleprinter. Discrete multi-tone modulation modes such as Multi Tone 63 (MT63) Multiple frequency-shift keying (MFSK) modes such as. FSK441, JT6M, JT65, and FT8.
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time ...
Secondary surveillance radar (SSR) is a radar system used in air traffic control (ATC), that unlike primary radar systems that measure the bearing and distance of targets using the detected reflections of radio signals, relies on targets equipped with a radar transponder, that reply to each interrogation signal by transmitting encoded data such ...
Passive radar. Passive radar (also referred to as parasitic radar, passive coherent location, passive surveillance, and passive covert radar) is a class of radar systems that detect and track objects by processing reflections from non-cooperative sources of illumination in the environment, such as commercial broadcast and communications signals.