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CHU (radio Station)
CHU is the call sign of a shortwave time signal radio station operated by the Institute for National Measurement Standards of the National Research Council. CHU's signal is used for continuous dissemination of official Canadian government time signals, derived from atomic clocks. History Radio time signals allowed accurate and rapid distribution of time signals beyond the range of the telegraph or visual signals. This was of particular value in surveying remote areas, where time signals allowed accurate determination of longitude. In the summer of 1914, a survey party at Quinze Dam in the Ottawa River watershed attempted to receive time signals transmitted from Kingston; however, signals were not resolvable and the time signal from NAA in Arlington, Virginia was used instead.Malcolm M. Thomson, ''The Beginning of the Long Dash: A History of Timekeeping in Canada'', University of Toronto Press, 1978, ,1 Chapter 6 The station was started in 1923 by the Dominion Observatory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ottawa
Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern Ontario, southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core of the Ottawa–Gatineau census metropolitan area (CMA) and the National Capital Region (Canada), National Capital Region (NCR). Ottawa had a city population of 1,017,449 and a metropolitan population of 1,488,307, making it the list of the largest municipalities in Canada by population, fourth-largest city and list of census metropolitan areas and agglomerations in Canada, fourth-largest metropolitan area in Canada. Ottawa is the political centre of Canada and headquarters to the federal government. The city houses numerous List of diplomatic missions in Ottawa, foreign embassies, key buildings, organizations, and institutions of Government of Canada, Canada's government, including the Parliament of Canada, the Supreme Cour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingston, Ontario
Kingston is a city in Ontario, Canada. It is located on the north-eastern end of Lake Ontario, at the beginning of the St. Lawrence River and at the mouth of the Cataraqui River (south end of the Rideau Canal). The city is midway between Toronto, Ontario and Montreal, Quebec. Kingston is also located nearby the Thousand Islands, a tourist region to the east, and the Prince Edward County tourist region to the west. Kingston is nicknamed the "Limestone City" because of the many heritage buildings constructed using local limestone. Growing European exploration in the 17th century, and the desire for the Europeans to establish a presence close to local Native occupants to control trade, led to the founding of a French trading post and military fort at a site known as "Cataraqui" (generally pronounced /kætə'ɹɑkweɪ/, "kah-tah-ROCK-way") in 1673. This outpost, called Fort Cataraqui, and later Fort Frontenac, became a focus for settlement. Since 1760, the site of Kingston, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Interference
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science. EMI can be used intentionally for radio jamming, as in electronic warfare. History Since the earliest days of rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Clocks
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, \Delta \nu_\mathsf, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This definition is the basis for the system of International Atomic Time (TAI), which is maintained by an ensemble of atomic clocks around the world. The system of Coordinated Universal Time (UTC) that is the basis of civil time implements leap seconds to allow cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, \Delta \nu_\mathsf, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This definition is the basis for the system of International Atomic Time (TAI), which is maintained by an ensemble of atomic clocks around the world. The system of Coordinated Universal Time (UTC) that is the basis of civil time implements leap seconds to allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadian Broadcasting Corporation
The Canadian Broadcasting Corporation (french: Société Radio-Canada), branded as CBC/Radio-Canada, is a Canadian public broadcaster for both radio and television. It is a federal Crown corporation that receives funding from the government. The English- and French-language service units of the corporation are commonly known as CBC and Radio-Canada, respectively. Although some local stations in Canada predate the CBC's founding, CBC is the oldest existing broadcasting network in Canada. The CBC was established on November 2, 1936. The CBC operates four terrestrial radio networks: The English-language CBC Radio One and CBC Music, and the French-language Ici Radio-Canada Première and Ici Musique. (International radio service Radio Canada International historically transmitted via shortwave radio, but since 2012 its content is only available as podcasts on its website.) The CBC also operates two terrestrial television networks, the English-language CBC Television and the Fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry Mannis
Harry Mannis (April 11, 1920 - January 2, 2003) was a Canadian broadcaster who worked for the Canadian Broadcasting Corporation.https://www.ogs.on.ca/ogspi_pages/2003/o2003cbh.htm Harry Mannis, retrieved February 4, 2018 He joined the CBC in 1946 after serving with the Royal Canadian Air Force in the United Kingdom during World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ... and retired in the mid-1980s. He recorded time announcements for the shortwave time signal radio station CHU.Malcolm M. Thomson, ''The Beginning of the Long Dash: A History of Timekeeping in Canada'', University of Toronto Press, 1978, ,1 pp. 160,162 The audio of Mannis' time announcements was stored optically, on spinning discs at the National Research Council (Canada) in Ottawa. As of January 2022 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audichron
{{unsourced, date=April 2021 Audichron was a talking clock, or a time announcer which was developed and produced by the Audichron Company Audichron Company was a company founded in the 1930s by John Franklin in Doraville, Georgia, to produce the Audichron, a talking clock. By the 1970s, there were thousands of Audichron time-of-day announcers in use all over the world. Audichron had a ..., starting in the 1930s. There were several types of Audichron machines including the stand time piece (STM), M12, temperature machine (TEMP) and the Comparator. Types STM STM stood for "Small Town Machine". This was the standard time piece. It made announcements such as: "''Save by the 10th, earn from the first, at Central Brevard National Bank. Time one forty two.''" The STM had three recording drums and two sound heads. The drum on the left side of the machine was the widest; it held the customers' messages. On the right side of the machine were the hour drum and the minute drum. The hour dru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speaking Clock
A speaking clock or talking clock is a live or recorded human voice service, usually accessed by telephone, that gives the correct time. The first telephone speaking clock service was introduced in France, in association with the Paris Observatory, on 14 February 1933. The format of the service is similar to that of radio time signal services. At set intervals (''e.g.'' ten seconds) a voice announces (for example) "At the third stroke, the time will be twelve forty-six and ten seconds...", with three beeps following. Some countries have sponsored time announcements and include the sponsor's name in the message. List by country Australia In Australia, the number 1194 was the speaking clock in all areas. The service started in 1953 by the Post Master General's Department, originally to access the talking clock on a rotary dial phone, callers would dial "B074", during the transition from a rotary dial to a DTMF based phone system, the talking clock number changed from "B074" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the inventors of the telegraph. International Morse code encodes the 26 basic Latin letters through , one accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF (millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
