Editing Beacon

{{Short description|Device used to attract attention}}
{{for-multi|the fire signal|Beacon (signal fire)|other uses|Beacon (disambiguation)}}
A '''beacon''' is an intentionally conspicuous device designed to attract attention to a [[Geodetic datum|specific location]]. A common example is the [[lighthouse]], which draws attention to a fixed point that can be used to navigate around obstacles or into port. More modern examples include a variety of [[radio beacon]]s that can be read on [[radio direction finder]]s in all weather, and [[Transponder|radar transponder]]s that appear on [[radar]] displays.

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 [[aerodrome beacon|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 [[Telegraph#Optical telegraph|optical telegraphy]].

== For navigation ==
[[File:Beacon at Orontes Bank.jpg|right|thumb|A navigational beacon denoting the presence of Orontes Bank off [[Port Vincent, South Australia]].]]

Beacons help guide [[navigation|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 [[lighthouse]]s or light stations and can be located on land or on water. Lighted beacons are called ''lights''; unlighted beacons are called ''[[Day beacon|daybeacon]]s''. [[Aerodrome beacon]]s are used to indicate locations of airports and helipads.<ref>{{Cite journal |last=Mackall |first=K.W. |date=1931-11-01 |title=U.S. Aerodrome Lighting |url=https://doi.org/10.1108/eb029474 |journal=Aircraft Engineering and Aerospace Technology |volume=3 |issue=11 |pages=285–290 |doi=10.1108/eb029474 |issn=0002-2667|url-access=subscription }}</ref>

In the United States, a series of beacons were constructed across the country in the 1920s and 1930s to help guide pilots delivering [[air mail]]. They were placed about 25 miles apart from each other, and included large concrete arrows with accompanying lights to illuminate them.<ref>{{Cite news |last=Street |first=Francesca |date=2018-07-11 |title=The mysterious giant arrows used by airplanes |url=https://www.cnn.com/travel/article/concrete-arrows-america/index.html |access-date=2024-08-27 |website=CNN |language=en}}</ref>

Handheld beacons are also employed in [[aircraft marshalling]], and are used by the marshal to deliver instructions to the crew of aircraft as they move around an active airport, heliport or aircraft carrier.{{citation needed|date=August 2024}}

== For defensive communications (historical) ==
[[File:Culmstock, Culmstock Beacon - geograph.org.uk - 213525.jpg|thumb|left|16th-century beacon hut in [[Culmstock]], Devon, England]]

Historically, beacons were fires lit at well-known locations on hills or high places, used either as [[lighthouse]]s for [[navigational aid|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 telegraph]] and were part of a [[relay league]].

Systems of this kind have existed for centuries over much of the world. The ancient Greeks called them ''[[phryctoriae]]'', while beacons figure on several occasions on the [[column of Trajan]].

In imperial China, sentinels on and near the [[Great Wall|Great Wall of China]] used a sophisticated system of daytime smoke and nighttime flame to send signals along long chains of beacon towers.<ref name="travelchinaguide.com">{{Cite web|url=https://www.travelchinaguide.com/china_great_wall/construction/tower/|title=China Great Wall Beacon Towers: Chinese Oldest Telegram System|website=www.travelchinaguide.com|access-date=2020-04-26}}</ref>

Legend has it that [[King You of Zhou]] played a trick multiple times in order to amuse his often melancholy concubine, ordering beacon towers lit to fool his vassals and soldiers. But when enemies, led by the [[Marquess of Shen (King Ping's grandfather)|Marquess of Shen]] really arrived at the wall, although the towers were lit, no defenders came, leading to King Yōu's death and the collapse of the Western Zhou dynasty.<ref name="travelchinaguide.com"/><ref>{{cite book|year=1999|pages=546, 551|isbn=9781139053709|doi=10.1017/CHOL9780521470308 |title=The Cambridge History of Ancient China |last1=Loewe |first1=Michael |last2=Shaughnessy |first2=Edward L. }}</ref><ref>{{cite book|last=Giles|first=Herbert A.|year=1912|title=The Civilization of China|publisher=Tutis Digital Publishing|isbn=8132004485|chapter=1}}</ref> China's system of beacon towers was not extant prior to the [[Han dynasty]].

[[Thucydides]] wrote that during the [[Peloponnesian War]], the [[Peloponnese|Peloponnesians]] who were in [[Corcyra]] were informed by night-time beacon signals of the approach of sixty Athenian vessels from [[Lefkada]].<ref>[https://www.perseus.tufts.edu/hopper/text?doc=urn:cts:greekLit:tlg0003.tlg001.perseus-grc1:3.80 Thucydides, Peloponnesian War, 3.80]</ref>

In the 10th century, during the [[Arab–Byzantine wars]], the [[Byzantine Empire]] used a [[Byzantine beacon system|beacon system]] to transmit messages from the border with the [[Abbasid Caliphate]], across [[Anatolia]] to the [[Great Palace of Constantinople|imperial palace]] in the Byzantine capital, [[Constantinople]]. It was devised by [[Leo the Mathematician]] for Emperor [[Theophilos (emperor)|Theophilos]], but either abolished or radically curtailed by Theophilos' son and successor, [[Michael III]].<ref name="ODB">{{cite encyclopedia | last = Foss | first = Clive | title = Beacon | editor-last=Kazhdan | editor-first=Alexander | editor-link=Alexander Kazhdan |year=1991 | encyclopedia =[[The Oxford Dictionary of Byzantium]] | publisher=Oxford University Press |isbn=978-0-19-504652-6 | pages=273–274}}</ref> Beacons were later used in Greece as well, while the surviving parts of the beacon system in Anatolia seem to have been reactivated in the 12th century by Emperor [[Manuel I Komnenos]].<ref name="ODB" />

{{multiple image
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| image1            = Vårdkasen på Korpberget.jpg
| alt1              = A beacon in Sweden before being lit
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| image2            = Vårdkasen på Korpberget 2012a 01.jpg
| alt2              = A beacon in Sweden after being lit
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| footer            = A Beacon in Sweden before and after being lit
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In the Nordic countries, [[Hillfort|hill forts]] and beacon networks were important for warning against invasions.<ref name=":1">{{Cite web |title=Vårdkasar |url=https://1719.se/vrdkasar |access-date=2025-04-07 |website=1719 |language=en-US}}</ref> In Sweden and Finland, these beacons, known as ''vårdkasar'' or ''böte'', formed an extensive coastal warning system from the Late Iron Age and through the Middle Ages. Beacons were strategically placed on high ground for visibility, constructed from [[tar]]-rich wood to ensure bright flames. They were mentioned in medieval laws like ''[[Upplandslagen]]'' and described by Swedish writer [[Olaus Magnus]] in 1555 as tools for mobilising armed defenders during crises.<ref name=":1" /> In Finland, similar beacons called ''vainovalkeat'' ("persecution fires") or ''vartiotulet'' ("guard fires") warned settlements of raids. <ref>{{Cite web |title=Forneld |url=https://www.vskylat.fi/hankkeet-kotiseutukompassi-keistio-forneld/ |access-date=2025-04-07 |website=Varsinais-Suomen Kylät |language=fi}}</ref>

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 England the authority to erect beacons originally lay with the King and later was delegated to the [[Lord High Admiral of the United Kingdom|Lord High Admiral]]. The money due for the maintenance of beacons was called ''Beaconagium'' and was levied by the sheriff of each county.<ref>{{cite book|title=The National Cyclopaedia of Useful Knowledge, Volume 3|year=1847|first=Charles|last=Knight|location=London|page=25|url=https://granthsanjeevani.com/jspui/handle/123456789/70551}}</ref> In the [[Scottish border]]s country, a system of beacon fires was at one time established to warn of incursions by the English. [[Hume Castle|Hume]] and Eggerstone castles and Soltra Edge were part of this network.<ref>{{cite book|last=Ritchie|first=Leitch|year=1835|title=Scott and Scotland|location=London|publisher=Longman, Rees, Orme, Brown, Green, and Longman|page=53}}</ref>

In Spain, the border of [[Granada]] in the territory of the [[Crown of Castile]] had a complex beacon network to warn against Moorish raiders and military campaigns.<ref>Els almogávers a la frontera amb el sarrains en el segle XIV. Maria Teresa Ferrer</ref> Due to the progressive advance of the borders throughout the process of the Reconquista, the entire Spanish geography is full of defensive lines of castles, towers and fortifications, visually connected to each other, which served as fortified beacons. Some examples are the Route of the Vinalopó castles or the distribution of the castles in Jaén.

=== Ceremonial Use ===
In later centuries, advancements in technology, such as the [[Telegraphy|telegraph]], rendered beacon systems obsolete for rapid communication.<ref>{{Cite web |title=Queen's Platinum Jubilee: Why are beacons lit for big royal events? |url=https://news.sky.com/story/queens-platinum-jubilee-why-are-beacons-lit-for-big-royal-events-12624095 |access-date=2025-04-07 |website=Sky News |language=en}}</ref> The use of such beacons transitioned from practical communication to symbolic and ceremonial roles,<ref name=":0">{{Cite web |date=2024-06-02 |title=Beacon of light to honour braver' during D-Day landings |url=https://www.bbc.com/news/articles/cd115jl1xnpo |access-date=2025-04-07 |website=www.bbc.com |language=en-GB}}</ref> where the lighting of beacons was repurposed to mark significant national events. 

Beacons were lit across the United Kingdom to celebrate Queen Victoria's [[Diamond Jubilee of Queen Victoria|Diamond Jubilee]] in 1897, Queen Elizabeth II's [[Platinum Jubilee of Elizabeth II|Platinum Jubilee in 2022]],<ref>{{Cite web |date=2022-06-03 |title=Jubilee beacons in locations around U.K. celebrate Queen Elizabeth II… |url=https://archive.today/20220603021619/https://www.washingtonpost.com/world/2022/06/02/jubilee-beacons-locations/ |access-date=2025-04-07 |website=archive.is}}</ref> and to commemorate events such as the 70th anniversary of [[Victory in Europe Day|VE Day]], and the 80th anniversary of the [[Normandy landings|D-Day landings]] in 2024.<ref name=":0" />

South Korea maintains a daily ceremonial beacon lighting at [[Namsan]] Beacon Mound in [[Seoul]], where visitors witness a reenactment of the traditional ''bongsu'' ceremony, which historically signaled emergencies.<ref>{{Cite web |date=2008-11-20 |title=Beacon Ceremony at Namsan Beacon Mound - The Korea Times |url=https://www.koreatimes.co.kr/photos/photonews/20081120/beacon-ceremony-at-namsan-beacon-mound |access-date=2025-04-07 |website=www.koreatimes.co.kr |language=en}}</ref>

==Military use (20th–21st century)==
=== Infrared marker===
[[File:IR strobe closeup.jpg|thumb|A CORE Survival HEL-STAR 6 IR strobe mounted atop this marine's helmet]]
[[Infrared]] strobes and other infrared beacons have increasingly been used in modern combat when operating at night as they can only be seen through [[Night-vision device|night vision goggles]]. As a result, they are often used to mark friendly positions as a form of [[Identification friend or foe|IFF]] to prevent friendly fire and improve coordination. Soldiers will typically affix them to their [[Combat helmet|helmets]] or other gear so they are easily visible to others using night vision including other infantry, ground vehicles, and aerial platforms (drones, helicopters, planes, etc.).<ref name="light discipline">{{cite web |last1=Tishman |first1=Jon |last2=Schoen |first2=Dan |title=We Don't Own the Night Anymore |url=https://mwi.usma.edu/we-dont-own-the-night-anymore/ |website=Modern War Institute at West Point |access-date=4 June 2022 |archive-url=https://web.archive.org/web/20210122101518/https://mwi.usma.edu/we-dont-own-the-night-anymore/ |archive-date=22 January 2021 |date=22 January 2021}}</ref>

Passive markers include IR patches, which reflect infrared light, and [[chemlight]]s. The earliest such beacons were often IR chemlights taped to helmets.

As time went on, more sophisticated options began to emerge with electronically powered infrared strobes with specific mounting solutions for attaching to helmets or load bearing equipment. These strobes may have settings which allow constant on or strobes of IR light, hence the name.<ref name="hardhead vet">{{cite web |title=Identification Friend or Foe (IFF) Ballistic Helmet Markers |url=https://www.hardheadveterans.com/blogs/reviews/identification-friend-or-foe-iff-ballistic-helmet-markers |website=Hard Head Veterans |access-date=5 July 2022 |archive-url=https://web.archive.org/web/20211027190631/https://www.hardheadveterans.com/blogs/reviews/identification-friend-or-foe-iff-ballistic-helmet-markers |archive-date=27 October 2021 |date=19 February 2018}}</ref>

Advancements in near-peer technology, however, present risk since if friendly units can see the strobe with night vision so could enemies with night vision capabilities. As a result, some in the American military have stressed that efforts should be made to improve training regarding light discipline (IR and visible) and other means of reducing a unit's visible signature.<ref name="light discipline"/>

== On vehicles ==
{{Main|Emergency vehicle lighting}}
[[File:Beacon positions.jpg|thumb|Beacon positions on police car]]

Vehicular beacons are rotating or flashing lights affixed to the top of a vehicle to attract the attention of surrounding vehicles and pedestrians. [[Emergency vehicle]]s 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 hazards (slow-moving vehicles, wide loads, tow trucks, security personnel, construction vehicles, etc.); green for volunteer firefighters or for medical personnel, and violet for funerary vehicles. Beacons may be constructed with [[Automotive lamp types|halogen bulbs]] similar to those used in vehicle [[headlamp]]s, xenon [[flashtube]]s, or [[light-emitting diode|LEDs]].<ref>{{cite journal
 |title=Evaluation of Light-Emitting Diode Beacon Light Fixtures 
 |journal=Lighting Research Center – Rensselaer Polytechnic Institute 
 |date=December 2009 
 |first=John 
 |last=Bullough 
 |author2=Nicholas P Skinner 
 |url=https://www.dot.ny.gov/divisions/engineering/technical-services/trans-r-and-d-repository/LRCBeaconReport.pdf 
 |access-date=2010-06-05 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20130729142629/https://www.dot.ny.gov/divisions/engineering/technical-services/trans-r-and-d-repository/LRCBeaconReport.pdf 
 |archive-date=2013-07-29 
}}</ref> 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.

== Other uses ==
Beacons have also allegedly been abused by [[Wrecking (shipwreck)|shipwreckers]]. An illicit fire at a wrong position would be used to direct a ship against [[shoal]]s or [[beach]]es, so that its cargo could be looted after the ship sank or ran aground. There are, however, no historically substantiated occurrences of such intentional shipwrecking.

In wireless networks, a [[Electric beacon#IEEE 802.11 Wi-Fi beacons|beacon]] is a type of [[Frame (networking)|frame]] which is sent by the access point (or WiFi router) to indicate that it is on.

Bluetooth based beacons periodically send out a data packet and this could be used by software to identify the beacon location. This is typically used by [[indoor positioning system|indoor navigation and positioning]] applications.<ref>{{cite web|url=https://kontakt.io/beacon-basics/what-is-a-beacon/ |title=What is a Beacon? - Beacon Basics |website=Kontakt.io |date=2016-09-20 |access-date=2017-04-05}}</ref>

''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.

=== In fiction ===
In [[Aeschylus]]' tragedy ''[[Oresteia|Agamemnon]]'',<ref>v. 281 ''et sqq.''</ref> a chain of eight beacons staffed by so-called ''lampadóphoroi'' inform [[Clytemnestra]] in [[Argos, Peloponnese|Argos]], within a single night's time, that [[Troy]] has just fallen under her husband king Agamemnon's control, after a famous [[Trojan War|ten years siege]].

In [[J. R. R. Tolkien]]'s [[high fantasy]] novel, ''[[The Lord of the Rings]]'', a [[Warning beacons of Gondor|series of beacons]] alerts the entire realm of [[Gondor]] when the kingdom is under attack. These beacon posts were staffed by messengers who would carry word of their lighting to either [[Rohan (Middle-earth)|Rohan]] or [[Belfalas]].<ref name=TolkienLotR>{{cite book|last=Tolkien|first=J. R. R.|title=The Lord of the Rings|year=2004|publisher=Houghton Mifflin Company|volume=[[The Return of the King]]|pages=747–748|edition=50th Anniversary }}</ref> In [[Peter Jackson]]'s [[The Lord of the Rings: The Return of the King|film adaptation of the novel]], the beacons serve as a connection between the two realms of Rohan and Gondor, alerting one another directly when they require military aid, as opposed to relying on messengers as in the novel.

=== In publishing ===
''[[The Beacon (magazine)|The Beacon]]'' was an influential Caribbean magazine published in Trinidad in the 1930s. [[New Beacon Books]] was the first Caribbean publishing house in England, founded in London in 1966, was named after the ''Beacon'' journal.<ref>{{cite book|last=Phillips|first=Caryl|title=[[Colour Me English]]|year=2011|publisher=Random House|location=London|isbn=9781409028925|chapter-url=https://books.google.com/books?id=Eia2VYteDwwC&dq=new+beacon+books+publishing+house&pg=PT111|author-link=Caryl Phillips|chapter=John La Rose}}</ref>

=== In retail ===
Beacons are sometimes used in retail to send digital coupons or invitations to customers passing by.<ref>{{cite web |author=Peter Lewis |url=https://www.thinkwithgoogle.com/articles/retail-marketing-beacon-technology.html |title=How Beacons Can Reshape Retail Marketing – Think with Google |website=Thinkwithgoogle.com |date=2016-08-19 |access-date=2017-04-05 |archive-date=2017-05-03 |archive-url=https://web.archive.org/web/20170503041241/https://www.thinkwithgoogle.com/articles/retail-marketing-beacon-technology.html |url-status=dead }}</ref><ref>{{cite journal|title=Analysis of Promising Beacon Technology for Consumers|journal=Elon Journal of Undergraduate Research in Communications|date=Spring 2015|volume=6|issue=1|url=https://eloncdn.blob.core.windows.net/eu3/sites/153/2017/06/EJSpring15_Full.pdf|page=59|first=Marisa|last=Moody}}</ref>

==Types==
=== Infrared beacon ===
{{Expand section|date=June 2008}}

An infrared beacon (IR beacon) transmits a modulated light beam in the infrared spectrum, which can be identified easily and positively. A line of sight clear of obstacles between the transmitter and the receiver is essential. IR beacons have a number of applications in [[robotics]] and in [[Combat Identification]] (CID).

Infrared beacons are the key infrastructure for the Universal Traffic Management System (UTMS) in Japan. They perform two-way communication with travelling vehicles based on highly directional infrared communication technology and have a vehicle detecting capability to provide more accurate traffic information.<ref>{{cite web
| url=http://www.utms.or.jp/english/beacon/index.html
| publisher=Universal Traffic Management Society of Japan
| title=Infrared Beacon Overview
| access-date=2008-04-27
| year=2007 }}</ref>

=== Sonar beacon ===
{{Expand section|date=September 2012}}
A sonar beacon is an underwater device which transmits sonic or ultrasonic signals for the purpose of providing bearing information. The most common type is that of a rugged watertight sonar transmitter attached to a submarine and capable of operating independently of the electrical system of the boat. It can be used in cases of emergencies to guide salvage vessels to the location of a disabled submarine.<ref>{{Cite web |url=http://www.elac-nautik.de/_uploads/images/pdf/L-3%20ELAC%20Nautik%20SBE.pdf |title=The ELAC SBE distress sonar beacon |access-date=2019-04-05 |archive-date=2013-03-20 |archive-url=https://web.archive.org/web/20130320005728/http://www.elac-nautik.de/_uploads/images/pdf/L-3%20ELAC%20Nautik%20SBE.pdf |url-status=dead }}</ref>

== See also ==
* [[Aerodrome beacon]]
* [[Beacon mode service]]
* [[Beacon Status|Beacon School]]
* [[Belisha beacon]]
* [[Emergency locator beacon]]
* [[Emergency position-indicating radiobeacon station]] (ELTs, PLBs & EPIRBs)
* [[iBeacon]]
* [[Lantern]]
* [[Leading lights]]
* [[Lighthouse of Alexandria]]
* [[Milestone]]/[[Kilometric point]]
* [[Polaris]]
* [[Signal]]
* [[Strobe beacon]]
* [[Time ball]]
* [[Trail blazing]]
* [[Warning light (disambiguation)]]
* [[Weather beacon]]
* [[Web beacon]]

==References==
{{Reflist}}

{{Morse code}}
{{Telecommunications}}
{{Authority control}}
{{Wikiquote}}

[[Category:Beacons| ]]