Beacon
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(navigation) A light, group of lights, electronic apparatus, or other device which emits identifying signals related to their positions so that the information so produced can be used by the navigator or pilots of aircraft and ships for guidance orientation or warning. A structure where such a device is mounted or located.
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beaconing
(1) A continuous signaling of error conditions on a local network (LAN). In a token ring network, a beacon frame is sent by the adapter if a failure in the line is detected. See beacon removal.
(2) In a wireless network, the continuous transmission of small packets (beacons) that advertise the presence of a base station (access point). The mobile units sense the beacons and attempt to establish a wireless connection. See Wi-Fi hotspot and wireless LAN.
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n. 1. a fire or light set up in a high or prominent position as a warning, signal, or celebration.
2. a light or other visible object serving as a signal, warning, or guide, especially at sea or on an airfield.
3. a radio transmitter whose signal helps to fix the position of a ship, aircraft, or spacecraft.
See the Introduction, Abbreviations and Pronunciation for further details.
Columbia Encyclopedia:
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beacon
Beacon, city (1990 pop. 13,243), Dutchess co., SE N.Y., on the E bank of the Hudson River; settled 1663, inc. in 1913 when Fishkill Landing and Matteawan villages were united. Beacon's textile, printing, and other industries have declined, but the opening of Dia:Beacon, the world's largest museum of contemporary art, has stimulated a revival of the city. The Newburgh-Beacon Bridge connects the city with Newburgh on the west bank. An incline railway ascends Mt. Beacon, site of a monument to Revolutionary soldiers who built signal fires to warn of the coming of the British.
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Beacon, NY
Journal presenting the teachings of Alice A. Bailey (1880-1949), former Theosophist who founded her own Arcane School. Address: Lucis Publishing Co., 113 University Pl., 11th Fl., Box 722, Cooper Sta., New York, NY 10017.
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Beacon
For other uses, see Beacon (disambiguation).
A beacon is an intentionally conspicuous device designed to attract attention to a specific location.
Beacons can also be combined with semaphoric or other indicators to provide important information, such as the status of an airport, by the colour and rotational pattern of its airport beacon, or of pending weather as indicated on a weather beacon mounted at the top of a tall building or similar site. When used in such fashion, beacons can be considered a form of optical telegraphy.
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Beacons help guide navigators to their destinations. Types of navigational beacons include radar reflectors, radio beacons, sonic and visual signals. Visual beacons range from small, single-pile structures to large lighthouses or light stations and can be located on land or on water. Lighted beacons are called lights; unlighted beacons are called daybeacons.
Beaconing is the process that allows a network to self-repair network problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.
For defensive communications
Classically, beacons were fires lit at well-known locations on hills or high places, used either as lighthouses for navigation at sea, or for signalling over land that enemy troops were approaching, in order to alert defenses. As signals, beacons are an ancient form of optical telegraphy, and were part of a relay league.
Systems of this kind have existed for centuries over much of the world. In Scandinavia many hill forts were part of beacon networks to warn against invading pillagers. In Wales, the Brecon Beacons were named for beacons used to warn of approaching English raiders. In England, the most famous examples are the beacons used in Elizabethan England to warn of the approaching Spanish Armada. Many hills in England were named Beacon Hill after such beacons. In the Scottish borders country a system of beacon fires were at one time established to warn of incursions by the English. Hume, Eggerstone castle and Soltra Edge were part of this network.[1] The Great Wall of China is actually a beacon network too.
On vehicles
Vehicular beacons are rotating or flashing lights affixed to the top of a vehicle to attract the attention of surrounding vehicles and pedestrians. Emergency vehicles such as fire engines, ambulances, police cars, tow trucks, construction vehicles, and snow-removal vehicles carry beacon lights.
The color of the lamps varies by jurisdiction; typical colors are blue and/or red for police, fire, and medical-emergency vehicles; amber for tow trucks, security personnel, and construction vehicles; green for volunteer firefighters, and violet for funerary vehicles. Beacons may be constructed with halogen bulbs similar to those used in vehicle headlamps, xenon flashtubes, or LEDs.[2] Incandescent and xenon light sources require the vehicle’s engine to continue running to ensure that the battery is not depleted when the lights are used for a prolonged period. The low power consumption of LEDs allows the vehicle's engine to remain turned off while the lights operate nodes.
Other uses
Beacons and bonfires are also used to mark occasions and celebrate events. In Israel beacons identify the beginning of the month.
Beacons have also been abused by pirates. An illicit fire at a wrong position could be used to direct a ship against shoals or beaches, so that its cargo could be looted after the ship sank or ran aground.
In wireless networks, a beacon is a type of packet which is made by the router to indicate when it is turned on.
In fiction, culture, politics
- In The Lord of the Rings, a series of seven beacons is used as a signaling device between Gondor and Rohan.[3] In the film adaptation of The Return of the King, Gandalf has Pippin light the beacon closest to Minas Tirith. The series is then lit, thereby notifying Rohan's King Théoden of Gondor's calls for help in the battle against Sauron.
- Beacon of Hope (sculpture), Ireland
- The light on the hill, a speech of Benedict Chifley
- Paul Revere's Ride, a poem by Henry Wadsworth Longfellow (historic use of a lantern as a signal, akin to a beacon)
See also
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References
- ^ Ritchie, Leitch (1835). Scott and Scotland. London : Longman, Rees, Orme, Brown, Green, and Longman. p. 53
- ^ Bullough, John; Nicholas P Skinner (2009-12). "Evaluation of Light-Emitting Diode Beacon Light Fixtures" (PDF). Lighting Research Center - Rensselaer Polytechnic Institute. http://www.nysdot.gov/divisions/engineering/technical-services/trans-r-and-d-repository/LRCBeaconReport.pdf. Retrieved 2010-06-05.
- ^ Beacons of Gondar
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