Telegraph Signal Tower at Cobb's Hill, near New Market, Virginia, 1864.

A Radio beacon is non-directional transmitter that usually transmits a constant signal on a specified radio frequency. Image File history File links Download high resolution version (1095x1403, 343 KB)Signal Tower at Cobbs Hill, near New Market, Virginia, 1864. ... Image File history File links Download high resolution version (1095x1403, 343 KB)Signal Tower at Cobbs Hill, near New Market, Virginia, 1864. ... Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ... In telecommunication, signalling (or signaling) has the following meanings: The use of signals for controlling communications. ... Rough plot of Earths atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including radio waves. ...

Before the days of VOR, GPS, LORAN, beacons were used with direction finding equipment to find ones relative bearing to a known location (the beacon). D-VOR (Doppler VOR) ground station, co-located with DME. VOR, short for VHF Omni-directional Radio Range, is a type of radio navigation system for aircraft. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... LORAN (LOng RAnge Navigation) is a terrestrial navigation system using low frequency radio transmitters that use the time interval between radio signals received from three or more stations to determine the position of a ship or aircraft. ... In navigation, a bearing is the angle between the direction to an object and a reference direction. ...

There are several different kinds of beacons. In aviation there is a beacon called NDB or Non-directional Beacon. These are used to help find airports and conduct instrument approaches. These beacons will be decommissioned over the next few years as they have been replaced with newer better technologies. There also in the past were marine beacons for use at sea, but most cases these no longer are in service. There are also Amateur radio beacons that are used to test propagation of radio signals. Beacons are also use in both geostationary and inclined orbit satellites. Any satellite will emit one or more beacons (normally at a fixed frequency) whose purpose is two fold; as well as containing modulated station keeping information, the beacon is used to 'find' the satellite in the sky. Any AM, VHF, or UHF radio station can also be used as a beacon with Direction finding A non-directional beacon (NDB) is a radio broadcast station in a known location, used as an aviation or marine navigational aid. ... Amateur radio, often called ham radio, is a hobby enjoyed by about 3 million people[1] throughout the world. ... The word propagation can mean: Multiplication or increase, as by natural reproduction. ... A geostationary orbit (abbreviated GEO) is a circular orbit in the Earths equatorial plane, any point on which revolves about the Earth in the same direction and with the same period as the Earths rotation. ... For the musical use of modulation, see modulation (music). ... Mediumwave radio transmissions (sometimes called Medium frequency or MF) are those between the frequencies of 300 kHz and 3000 kHz. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... This article is about the radio frequency. ... To meet Wikipedias quality standards and appeal to a wider international audience, this article may require cleanup. ... Direction finding (DF) refers to the establishment of the direction from which a received signal was transmitted. ...

List of NDBs