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These automatic signal clocks were synchronized by telegraphy in 1905 before the widespread use of radio
These automatic signal clocks were synchronized by telegraphy in 1905 before the widespread use of radio

A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Year 1905 ( MCMV) was a Common year starting on Sunday (link will display full calendar of the Gregorian calendar (or a Common year starting Radio is the transmission of signals by Modulation of electromagnetic waves with frequencies below those of visible Light.

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Audible and visible time signals

One sort of public time signal is, of course, a striking clock. A striking clock is a Clock that sounds the Hours audibly on a bell or Gong. These clocks, however, are only as good as the clockwork that activates them; they have improved substantially since the first surviving clocks from the fourteenth century. For many members of the general public, a public clock such as Big Ben was the only time standard they needed. The Clock Tower is the world's largest four-faced chiming Clock.

When more accurate public time signals were desired for use in navigation, a number of traditional audible or visible time signals were established for the purpose of allowing navigators to check their marine chronometers. Navigation is the process of reading and controlling the movement of a craft or vehicle from one place to another A marine chronometer is a timekeeper precise enough to be used as a portable Time standard; it can therefore be used to determine Longitude by means of Celestial These public time signals were formerly established in many seaport cities. ||-||-|-||-||-||-||-||-||-|} A port is a facility for receiving Ships and transferring cargo

As an example of such a signal, in Vancouver, British Columbia, a "9 O'Clock Gun" is still shot every night at 9 p. Vancouver (vænˈkuːvɚ is a coastal British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C The 9 O'Clock Gun is a Cannon located in Vancouver, British Columbia that is shot every night at 2100 (9 p m. . This gun was brought to Stanley Park by the Department of Fisheries in 1894 to warn fishermen of the 6:00 p. Stanley Park is a 4049 hectare (1000 acre Urban park bordering downtown Vancouver, British Columbia, Canada. Year 1894 ( MDCCCXCIV) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common A fisherman or fisher is someone who gathers Fish, Shellfish, or other animals from a body of water m. Sunday closing of fishing. The 9:00 p. m. firing was later established as a time signal for the general population. The Brockton Point lighthouse keeper, William D. Brockton Point is located in Vancouver harbor at the east end of Stanley Park. Jones, originally detonated a stick of dynamite until the Time Gun was installed. A similar "Noon Gun" is still shot every noon at Cape Town, South Africa. The Noon Gun has been a historic Time signal in Cape Town, South Africa since 1806 Cape Town (Kaapstad Xhosa: Ikapa) is the second most populous city in South Africa, forming part of the metropolitan municipality of the The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa A cannon was shot at one o'clock every weekday at Liverpool, England, at the Castle in Edinburgh, Scotland, and also at Perth in Australia to establish the time. Liverpool ( is a City and Metropolitan borough of Merseyside, England along the eastern side of the Mersey Estuary England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Edinburgh Castle is an ancient Stronghold which dominates the sky-line of the Edinburgh ( ˈɛdɪnb(ərə Dùn Èideann) is the Capital of Scotland and is its second largest city after Glasgow. Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. The Perth Observatory is an astronomical Observatory located in Bickley Western Australia, Australia. For a topic outline on this subject see List of basic Australia topics. The Edinburgh "One O'Clock Gun" is still in operation. Edinburgh Castle is an ancient Stronghold which dominates the sky-line of the A cannon located at the top of Santa Lucia Hill, in Santiago, Chile, is shot every noon. Santiago ( (litteraly in spanish Saint James) is the Capital of Chile, and the center of its largest Conurbation ( Greater Santiago In places where a cannon is used for a time signal, locals often joke that they can spot tourists because they jump in surprise while locals check their watches. In many Midwestern US cities where tornados are a common hazard, the emergency sirens are tested regularly at a specified time (such as, say, noon each Saturday); while this is not primarily intended as a time signal, locals often do check their watches when they hear it.

The ceremony of "dropping the ball" at New Year's Eve in Times Square in New York City is a vestige of a visual indication of time. New Year's Eve is on December 31, the final day of the Gregorian year and the day before New Year's Day. Times Square is a major intersection in Manhattan, New York City at the junction of Broadway and Seventh Avenue and stretching from West The City of New York The first such time ball was installed in 1833 on the roof of the Royal Observatory in Greenwich, England. Timeball stationjpg|thumb|right|The Port Lyttelton, New Zealand timeball started signaling Greenwich mean time to ships in the harbor beginning in 1876 The Royal Observatory Greenwich (formerly the Royal Greenwich Observatory or RGO) was commissioned in 1675 by King Charles II, with the Greenwich ( ˈɡrɛnɪtʃ GREN-itch /ˈɡrɛnɪdʒ/ GREN-idge or /ˈɡrɪnɪdʒ/ GRIN-idge is a district in south-east London, The ball was set to drop at 1 P. M. to enable the astronomers to establish the correct moment it should drop by observing the sun at noon. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study Liverpool, Edinburgh, and Perth also had balls that were dropped concurrently with the firing of the time cannons. Because the speed of light is much faster than the speed of sound, visible signals enabled greater precision than audible ones; however, the audible signals could operate under conditions of reduced visibility. Sound is a vibration that travels through an elastic medium as a Wave. In 1861 and 1862, the Post Office Directory had time gun maps published that related the number of seconds it took for the report of the time gun to reach various locations in Edinburgh. A map is a visual representation of an area—a symbolic depiction highlighting relationships between elements of that space such as objects, Regions, and Themes

In many non-seafaring communities, loud factory whistles served as public time signals before radio made them obsolete. A factory (previously manufactory) or manufacturing plant is an industrial Building where workers manufacture goods A simple whistle is a Woodwind instrument which produces Sound from a stream of forced air Radio is the transmission of signals by Modulation of electromagnetic waves with frequencies below those of visible Light.

Electrical time signals

Sandford Fleming proposed a single 24-hour clock for the entire world. Sir Sandford Fleming (January 7 1827 – July 22 1915 was a prolific Scottish-born Canadian Engineer and Inventor, known for introducing Universal At a meeting of the Royal Canadian Institute on February 8, 1879 he linked it to the anti-meridian of Greenwich (now 180°). Events 421 - Constantius III becomes co- Emperor of the Western Roman Empire. Year 1879 ( MDCCCLXXIX) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common Greenwich ( ˈɡrɛnɪtʃ GREN-itch /ˈɡrɛnɪdʒ/ GREN-idge or /ˈɡrɪnɪdʒ/ GRIN-idge is a district in south-east London, He suggested that standard time zones could be used locally, but they were subordinate to his single world time.

Standard time came into existence in the United States on November 18, 1883. Standard time is the result of synchronizing clocks in different geographical locations within a Time zone to the same time rather than using the local meridian as The United States of America —commonly referred to as the Events 326 - The old St Peter's Basilica is consecrated 1302 - Pope Boniface VIII issues the Papal bull Year 1883 ( MDCCCLXXXIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common Earlier, on October 11, 1883, the General Time Convention, forerunner to the American Railway Association, approved a plan that divided the United States into several time zones. Events 1138 - A massive earthquake struck Aleppo, Syria. 1531 - Huldrych Zwingli is killed Year 1883 ( MDCCCLXXXIII) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common The American Railway Association ( ARA) was an industry trade group representing railroads in the United States. On that November day, the United States Naval Observatory telegraphed a signal that coordinated noon at Eastern standard time with 11 a. The United States Naval Observatory ( USNO) is one of the oldest Scientific agencies in the United States. m. Central, 10 a. m. Mountain, and 9 a. m. Pacific standard time.

A March, 1905 issue of The Technical World describes the role of the United States Naval Observatory as a source of time signals:

One of the most important functions of the Naval Observatory is found in the daily distribution of the correct time to every portion of the United States. This is effected by means of telegraphic signals, which are sent out from Washington at noon daily, except Sundays. The original object of this time service was to furnish mariners in the seaboard cities with the means of regulating their chronometers; but, like many another governmental activity, its scope has gradually broadened until it has become of general usefulness. The electrical impulse which goes forth from the Observatory at noon each day, now sets or regulates automatically more than 70,000 clocks located in all parts of the United States, and also serves, in each of the larger cities of the country, to release a time-ball located on some lofty building of central location. The dropping of the time-ball — accompanied, at some points, with the simultaneous firing of a cannon — is the signal for the regulation by hand of hundreds of other clocks and watches in the vicinity.

Radio time sources

A modern LF Radio clock
A modern LF Radio clock

The telegraphic distribution of time signals was made obsolete by the use of AM, FM, shortwave radio, Internet Network Time Protocol servers as well as atomic clocks in GPS satellites. Low Frequency or LF refers to Radio Frequencies (RF in the range of 30 kHz&ndash300 kHz A radio clock is a Clock that is Synchronized by a Time code bit stream transmitted by a Radio transmitter connected to a Time standard Shortwave Radio operates between the frequencies of 3000 KHz (3 The Network Time Protocol ( NTP) is a protocol for distributing the Coordinated Universal Time (UTC by means of synchronizing the clocks of computer systems A server is a Computer dedicated to providing one or more services over a computer network typically through a request-response routine An atomic clock is a type of Clock that uses an Atomic resonance Frequency standard as its timekeeping element Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth

The following radio stations broadcast time in both audible and machine readable time code form that can be used as references for radio clocks and radio-controlled watches:

The audio portions of the WWV and WWVH broadcasts can also be heard by telephone. The time announcements are normally delayed by less than 30 ms when using land lines from within the continental United States, and the stability (delay variation) is generally < 1 ms. When mobile phones are used, the delays are often more than 100 ms due to the multiple access methods used to share cell channels. In rare instances when the telephone connection is made by satellite, the time is delayed by 250 to 500 ms. To hear these broadcasts, dial (303) 499-7111 for WWV (Colorado), and (808) 335-4363 for WWVH (Hawaii). Callers are disconnected after 2 minutes. These are not toll-free numbers; callers outside the local calling area are charged for the call at regular long distance rates.

A low cost LF radio clock receiver, antenna left, receiver right.
A low cost LF radio clock receiver, antenna left, receiver right. Low Frequency or LF refers to Radio Frequencies (RF in the range of 30 kHz&ndash300 kHz A radio clock is a Clock that is Synchronized by a Time code bit stream transmitted by a Radio transmitter connected to a Time standard

Loran-C time signals may also be used for radio clock synchronization, by augmenting their highly accurate frequency transmissions with external measurements of the offsets of LORAN navigation signals against time standards. LORAN ( LO ng R ange A id to N avigation is a terrestrial Radio navigation system using Low frequency Radio transmitters

Commercial broadcasts

In the United States, many information-based radio stations (full-service, all-news and news/talk) also broadcast time signals at the top of the hour. In New York, WOR, WCBS and WINS have distinctive top-of-the-hour tones, though the WINS signal is only approximate (several seconds error). The City of New York WOR is a class A (nighttime Clear channel) AM radio station located in New York New York, U WCBS (880 kHz often referred to as "WCBS Newsradio 880", is a Radio station in New York City. WINS (1010 kHz known on-air as "Ten-Ten WINS", is a radio station in New York City, owned by CBS Radio. WINS also has a tone at 30 minutes past the hour for those setting their clocks. Vancouver radio station CKNW also broadcasts time signals, using a chime every half-hour. Vancouver (vænˈkuːvɚ is a coastal CKNW owned by Corus Entertainment, is the highest-rated Talk radio station in Vancouver, British Columbia, Canada.

WCBS and many other CBS Radio Network affiliates air a "bong" (sounding A=440Hz) that immediately precedes each top-of-the-hour network newscast. The CBS Radio Network provides news sports and other programming to more than 1000 radio stations throughout the United States (The same bong could be heard on CBS Television Network affiliates in the 1970s. CBS Broadcasting Inc ( CBS) is an American radio and Television network. ) An automated "chirp" at one second before the hour signals a switch to the network broadcast.

In Los Angeles, KFWB broadcasts a tone precisely on the hour and half-hour during regular news broadcasts (although not during special programming such as baseball games. ) KNX also broadcasts a tone on the hour; however, this tone appears approximately 17 seconds late.

In Canada, the national non-commercial CBC Radio network broadcasts a daily NRC time signal at noon (Eastern Time, GMT-5) on French language Radio-Canada and one hour later on the English language CBC network. French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people English is a West Germanic language originating in England and is the First language for most people in the United Kingdom, the United States

Australia lacks an easily available source of accurate time. The VNG User's Consortium[1] is campaigning for the availability of accurate time in Australia, while developing ways around this problem. The Global Positioning System can also be used as a time reference for radio clocks, but require an accurate 1PPS output to be reliably used for time signals. Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth A device is being developed by the VNG User's Consortium that will convert GPS signals into an accurate time signal, to replace the now-defunct VNG service. VNG' was Australia 's national Time signal service It was inaugrated by the Australian Post Office on 21 September 1964

See also

References

External links

Dictionary

time signal

-noun

  1. a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day
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