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T10 (satellite)
T10 (formerly DirecTV-10) is a Boeing model 702 direct broadcast satellite that provides high-definition television (HDTV) to DirecTV subscribers in North America.Boeing Directv-10 specifications It was launched by on July 7, 2007 from the in aboard an [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DirecTV
DirecTV (trademarked as DIRECTV) is an American Multichannel television in the United States, multichannel video programming distributor based in El Segundo, California, El Segundo, California. Originally launched on June 17, 1994, its primary service is a digital Satellite television, satellite service serving the United States. It also provides traditional linear television service delivered by IP through its U-verse TV brand and a Multichannel_television_in_the_United_States#Virtual_MVPD,_TV_Everywhere,_and_over-the-top_media_services, Virtual MVPD service through its DirecTV Stream brand. Its primary competitors are Dish Network, traditional cable television providers, Multichannel_television_in_the_United_States#Wireline_and_broadband, IP-based television services, and other Over-the-top media service, over-the-top video services. On July 24, 2015, after receiving approval from the Federal Communications Commission and the United States Department of Justice, Department o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DirecTV-12
T12, formerly known as D12, is a Boeing model 702 satellite built by the Boeing Satellite Development Center. It was launched on December 29, 2009 and became operational on May 19, 2010. It is used by DirecTV to provide additional high definition channels and Video on demand content, as well as 3DTV channels and content. The satellite adopted its current name in 2017. Technology This satellite is similar to T10 and T11, but features a 17/24 GHz BSS payload carrying the moniker RB-2A. It is co-located with T10 very near 103.0°W. Launch data On November 27, the satellite was shipped to the Baikonur Cosmodrome in the Kazakhstan desert from the Boeing facility in El Segundo, California. T12 was launched successfully by International Launch Services on December 29, 2009 at 6:22 AM Kahzakstan time (00:22 UTC) [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellites In Geostationary Orbit
Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inquiry studying them. There are many disagreements about its precise definition. John Peters argues that the difficulty of defining communication emerges from the fact that communication is both a universal phenomenon and a specific discipline of institutional academic study. One definitional strategy involves limiting what can be included in the category of communication (for example, requiring a "conscious intent" to persuade). By this logic, one possible definition of communication is the act of developing meaning among entities or groups through the use of sufficiently mutually understood signs, symbols, and semiotic conventions. An important distinction is between verbal communication, which happens through the use of a language, and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Array
A photovoltaic system, also PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and convert sunlight into electricity, a solar inverter to convert the output from direct to alternating current, as well as mounting, cabling, and other electrical accessories to set up a working system. It may also use a solar tracking system to improve the system's overall performance and include an integrated battery. PV systems convert light directly into electricity, and are not to be confused with other solar technologies, such as concentrated solar power or solar thermal, used for heating and cooling. A solar array only encompasses the ensemble of solar panels, the visible part of the PV system, and does not include all the other hardware, often summarized as balance of system (BOS). PV systems range from small, rooftop-mounted or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bent Pipe
A communications satellite's transponder is the series of interconnected units that form a communications channel between the receiving and the transmitting antennas. It is mainly used in satellite communication to transfer the received signals. A transponder is typically composed of: * an input band-limiting device (an input band-pass filter), * an input low-noise amplifier (LNA), designed to amplify the signals received from the Earth station (normally very weak, because of the large distances involved), * a frequency translator (normally composed of an oscillator and a frequency mixer) used to convert the frequency of the received signal to the frequency required for the transmitted signal, * an output band-pass filter, * a power amplifier (this can be a traveling-wave tube or a solid-state amplifier). Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Most transponders opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spot Beam
A spot beam, in telecommunications parlance, is a satellite signal that is specially concentrated in power (i.e. sent by a high-gain antenna) so that it will cover only a limited geographic area on Earth. Spot beams are used so that only Earth stations in a particular intended reception area can properly receive the satellite signal.{{cite book, first=Michael Olorunfunmi, last= Kolawole, title=Satellite Communication Engineering, Second Edition, publisher =CRC Press , year=2013 , page=43 , isbn=9781138075351 One notable example of the use of spot beams is on direct broadcast satellite systems such as DirecTV and Dish Network that deliver local broadcast television via satellite only to viewers in the part of North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ... from which t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traveling Wave Tube Amplifier
A traveling-wave tube (TWT, pronounced "twit") or traveling-wave tube amplifier (TWTA, pronounced "tweeta") is a specialized vacuum tube that is used in electronics to amplify radio frequency (RF) signals in the microwave range. The TWT belongs to a category of "linear beam" tubes, such as the klystron, in which the radio wave is amplified by absorbing power from a beam of electrons as it passes down the tube. Although there are various types of TWT, two major categories are: *''Helix TWT'' - in which the radio waves interact with the electron beam while traveling down a wire helix which surrounds the beam. These have wide bandwidth, but output power is limited to a few hundred watts. *''Coupled cavity TWT'' - in which the radio wave interacts with the beam in a series of cavity resonators through which the beam passes. These function as narrowband power amplifiers. A major advantage of the TWT over some other microwave tubes is its ability to amplify a wide range of frequencie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ka-band
The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The band is called Ka, short for "K-above" because it is the upper part of the original NATO K band, which was split into three bands because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz (1.35 cm), which made the center unusable for long range transmission. The 30/20 GHz band is used in communications satellite uplinks in either the 27.5 GHz and 31 GHz bands, and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement. The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope. The designation "Ka- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplexor
A diplexer is a passive device that implements frequency-domain multiplexing. Two ports (e.g., L and H) are multiplexed onto a third port (e.g., S). The signals on ports L and H occupy disjoint frequency bands. Consequently, the signals on L and H can coexist on port S without interfering with each other. Typically, the signal on port L will occupy a single low frequency band and the signal on port H will occupy a higher frequency band. In that situation, the diplexer consists of a lowpass filter connecting ports L and S and high pass filter connecting ports H and S. Ideally, all the lowband signal power on port L is transferred to the S port and vice versa. All the highband signal power on port H is transferred to port S and vice versa. Ideally, the separation of the signals is complete. None of the low band signal is transferred from the L port to the H port. In the real world, some power will be lost, and some signal power will leak to the wrong port. The diplexer, being a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPEG-2
MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods, which permit storage and transmission of movies using currently available storage media and transmission bandwidth. While MPEG-2 is not as efficient as newer standards such as H.264/AVC and H.265/HEVC, backwards compatibility with existing hardware and software means it is still widely used, for example in over-the-air digital television broadcasting and in the DVD-Video standard. Main characteristics MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar discs. TV stations, TV receivers, DVD players, and other equipment are often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
