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Telstar 2
Telstar 2 was a communications satellite launched by NASA on May 7, 1963. It remained active for 2 years. Telstar 2 remains in orbit. History Telstar 2, primarily a communications satellite, carried an experiment designed to measure the energetic proton and electron distribution in the Van Allen belts. The spacecraft spin axis shortly after launch was about 80 deg to the ecliptic plane. The initial spin rate was 180 rpm, and it varied slowly over the life of the spacecraft. Telstar 2 was essentially identical to the Telstar 1 satellite. It employed two transmitters, and data were telemetered via a PCM/ FM/ AM encoder. The telemetry sequence required about 1 min. Telstar 2 differed from Telstar 1 by employing provisions for scientific information to be transmitted in real time via the microwave telemetry system so that telemetry could be obtained after the 2 years timer had turned off the VHF beacon. On May 16, 1965, at 1403 UT, during the satellite's 4736 orbit, the VHF transmit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AT&T
AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile telephone services in the U.S. , AT&T was ranked 13th on the ''Fortune'' 500 rankings of the largest United States corporations, with revenues of $168.8 billion. During most of the 20th century, AT&T had a monopoly on phone service in the United States. The company began its history as the American District Telegraph Company, formed in St. Louis in 1878. After expanding services to Arkansas, Kansas, Oklahoma and Texas, through a series of mergers, it became Southwestern Bell Telephone Company in 1920, which was then a subsidiary of American Telephone and Telegraph Company. The latter was a successor of the original Bell Telephone Company founded by Alexander Graham Bell in 1877. The American Bell Telephone Company formed the American Teleph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Telephone And Telegraph
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agencies. During the Bell System's long history, AT&T was at times the world's largest telephone company, the world's largest cable television operator, and a regulated monopoly. At its peak in the 1950s and 1960s, it employed one million people and its revenue ranged between US$3 billion in 1950 ($ in present-day terms) and $12 billion in 1966 ($ in present-day terms). In 2005, AT&T was purchased by Baby Bell and former subsidiary SBC Communications for more than $16 billion ($ in present-day terms). SBC then changed its name to AT&T Inc. Today, AT&T Corporation continues to exist as the long distance subsidiary of AT&T Inc., and its name occasionally shows up in AT&T press releases. Buildings with AT&T logo * AT&T Huro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleumeur-Bodou
Pleumeur-Bodou (; ) is a commune in the Côtes-d'Armor department of Brittany in northwestern France. Population Inhabitants of Pleumeur-Bodou are called ''pleumeurois'' in French. Sister town Pleuveur-Bodoù is twinned with Crosshaven, a village in Cork Harbour, Ireland. See also *Communes of the Côtes-d'Armor department *Telstar Telstar is the name of various communications satellites. The first two Telstar satellites were experimental and nearly identical. Telstar 1 launched on top of a Thor-Delta rocket on July 10, 1962. It successfully relayed through space the fir ... References External links * Communes of Côtes-d'Armor {{CôtesArmor-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brittany (administrative Region)
Brittany (french: Bretagne ; br, Breizh ); Gallo: ''Bertaèyn'' ) is the westernmost region of Metropolitan France. It covers about four fifths of the territory of the historic province of Brittany. Its capital is Rennes. It is one of the two Regions in Metropolitan France that does not contain any landlocked departments, the other being Corsica. Brittany is a peninsular region bordered by the English Channel to the north and the Bay of Biscay to the south, and its neighboring regions are Normandy to the northeast and Pays de la Loire to the southeast. " Bro Gozh ma Zadoù" is the anthem of Brittany. It is sung to the same tune as that of the national anthem of Wales, "Hen Wlad Fy Nhadau", and has similar words. As a region of France, Brittany has a Regional Council, which was most recently elected in 2021. Territory The region of Brittany was created in 1941 from four of the five departments constituting the territory of traditional Brittany. The other is Loire-A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to the south by the Straits of Florida and Cuba; it is the only state that borders both the Gulf of Mexico and the Atlantic Ocean. Spanning , Florida ranks 22nd in area among the 50 states, and with a population of over 21 million, it is the third-most populous. The state capital is Tallahassee, and the most populous city is Jacksonville. The Miami metropolitan area, with a population of almost 6.2 million, is the most populous urban area in Florida and the ninth-most populous in the United States; other urban conurbations with over one million people are Tampa Bay, Orlando, and Jacksonville. Various Native American groups have inhabited Florida for at least 14,000 years. In 1513, Spanish explorer Juan Ponce de León became the first k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very High Frequency
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves ( radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF). VHF radio waves propagate mainly by line-of-sight, so they are blocked by hills and mountains, although due to refraction they can travel somewhat beyond the visual horizon out to about 160 km (100 miles). Common uses for radio waves in the VHF band are Digital Audio Broadcasting (DAB) and FM radio broadcasting, television broadcasting, two-way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR and ILS) wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telemetry
Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek language, Greek roots ''tele'', "remote", and ''metron'', "measure". Systems that need external instructions and data to operate require the counterpart of telemetry, telecommand. Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or Infrared#Communications, infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. A ''telemeter'' is a physical device used in telemetry. It consists of a sensor, a transmission path, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the sidebands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280.2C1.29 RLL, computing. In Analog signal, analog frequency modulation, such as radio broadcasting, of an audio signal representing voice or music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies may represent digits, such as '0' and '1'. FSK is widely used in computer modems, such as fax modems, telephone caller ID systems, garage door openers, and other low-frequency transmissions. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic Plane
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Sun's apparent motion The ecliptic is the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours ... [...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 Transponder (satellite communications), transponders. Many satellites use a Satellite bus, standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming Satellite constellation, 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 Broadcast relay station, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
