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RG-6
RG-6/U is a common type of coaxial cable used in a wide variety of residential and commercial applications. An RG-6/U coaxial cable has a characteristic impedance of 75 ohms. The term, ''RG-6'', is generic and is applied to a wide variety of cable designs, which differ from one another in shielding characteristics, center conductor composition, dielectric type and jacket type. ''RG'' was originally a unit indicator 'Mike Meyers' CompTIA Network+ Certification Passport', by Glen E. Clark, edited by Christopher A. Crayton, McGraw-Hill, 3rd Edition, 2009, page 32. "Specific coax types were developed for the Ethernet standard, but a number of radio cables have very similar characteristics, and these so-called radio-grade (RG) cables also became associated with Ethernet." for bulk radio frequency (RF) cable in the U.S. military's Joint Electronics Type Designation System. The suffix ''/U'' means ''for general utility use''. The number was assigned sequentially. The ''RG'' unit indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coax Cable
Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a protective outer sheath or jacket. The term ''coaxial'' refers to the inner conductor and the outer shield sharing a geometric axis. Coaxial cable is a type of transmission line, used to carry high-frequency electrical signals with low losses. It is used in such applications as telephone trunk lines, broadband internet networking cables, high-speed computer data buses, cable television signals, and connecting radio transmitters and receivers to their antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line. Coaxial cable was used in the first (1858) and follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coaxial Cable
Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulator (electricity), insulating material); many coaxial cables also have a protective outer sheath or jacket. The term ''coaxial'' refers to the inner conductor and the outer shield sharing a geometric axis. Coaxial cable is a type of transmission line, used to carry high-frequency Signal, electrical signals with low losses. It is used in such applications as telephone trunk lines, Internet access, broadband internet networking cables, high-speed computer bus (computing), data buses, cable television signals, and connecting Transmitter, radio transmitters and Radio receiver, receivers to their Antenna (radio), antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RG-6 Coaxial Cable
RG-6/U is a common type of coaxial cable used in a wide variety of residential and commercial applications. An RG-6/U coaxial cable has a characteristic impedance of 75 ohms. The term, ''RG-6'', is generic and is applied to a wide variety of cable designs, which differ from one another in shielding characteristics, center conductor composition, dielectric type and jacket type. ''RG'' was originally a unit indicator 'Mike Meyers' CompTIA Network+ Certification Passport', by Glen E. Clark, edited by Christopher A. Crayton, McGraw-Hill, 3rd Edition, 2009, page 32. "Specific coax types were developed for the Ethernet standard, but a number of radio cables have very similar characteristics, and these so-called radio-grade (RG) cables also became associated with Ethernet." for bulk radio frequency (RF) cable in the U.S. military's Joint Electronics Type Designation System. The suffix ''/U'' means ''for general utility use''. The number was assigned sequentially. The ''RG'' unit indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drop (telecommunication)
In a communications network, a drop is the portion of a device directly connected to the internal station facilities, such as toward a telephone switchboard, toward a switching center, or toward a telephone exchange. A drop can also be a wire or cable from a pole or cable terminus to a building, in which case it may be referred to as a downlead. These cables may be reinforced to withstand the tension (due to gravity and weather) of an aerial drop (i.e., hanging in air), as in "messenger" type RG-6 coaxial cable, which is reinforced with a steel messenger wire along its length. Sources *Federal Standard 1037C, in support of MIL-STD-188 MIL-STD-188 is a series of U.S. military standards relating to telecommunications. Purpose Faced with "past technical deficiencies in telecommunications systems and equipment and software…that were traced to basic inadequacies in the appl ... External links * Drop Wire Information https://web.archive.org/web/20140419020353/http://www.dropwi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cable Television
Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over-the-air by radio waves and received by a television antenna, or satellite television, in which the television signal is transmitted over-the-air by radio waves from a communications satellite and received by a satellite dish on the roof. FM radio programming, high-speed Internet, telephone services, and similar non-television services may also be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation. A cable channel (sometimes known as a cable network) is a television network available via cable television. Many of the same channels are distributed throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RF Connector
An RF connector (radio frequency connector) is an electrical connector designed to work at radio frequencies in the multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission line impedance at the connection in order to reduce signal reflection and power loss. As the frequency increases, transmission line effects become more important, with small impedance variations from connectors causing the signal to reflect rather than pass through. An RF connector must not allow external signals into the circuit through electromagnetic interference and capacitive pickup. Mechanically, RF connectors may provide a fastening mechanism ( thread, bayonet, braces, blind mate) and springs for a low ohmic electric contact while sparing the gold surface, thus allowing very high mating cycles and reducing the insertion force. Research activity in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Cables
Telecommunications cable is a type of guided transmission medium. Telecommunications are based on transmitting and receiving modulated waves/signals through a medium. Types of telecommunications cable include: electrical cables when electric current is carried; transmission lines and waveguides when electromagnetic waves are transmitted; optical fibers when light signals are transmitted. When the distances involved are very short, the term ''signal cable'' may be used, for analog or digital communication. A ''data cable'' is used in digital data communications. Data cabling must conform to certain standards and best practices to ensure reliable performance and safety. When the distance between the transmitter and receiver is very far, an unguided or wireless medium transmission may be used, based on antennas. Examples include: * Ethernet cables ( Cat 5, Cat 5e, Cat 6, Cat 6A) * Token Ring cables ( Cat 4) * Coaxial cable mainly used for analog communication, sometimes used as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skin Effect
In electromagnetism, skin effect is the tendency of an alternating current, alternating electric current (AC) to become distributed within a Conductor (material), conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor. It is caused by opposing eddy currents induced by the changing magnetic field resulting from the alternating current. The electric current flows mainly at the ''skin'' of the conductor, between the outer surface and a level called the skin depth. Skin depth depends on the frequency of the alternating current; as frequency increases, current flow becomes more concentrated near the surface, resulting in less skin depth. Skin effect reduces the effective cross-section of the conductor and thus increases its effective electrical resistance, resistance. At 60 Hertz, Hz in copper, skin depth is about 8.5 mm. At high frequencies, skin depth becomes much smaller. Increased ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plenum Cable
__NOTOC__ Plenum cable is electrical cable that is laid in the plenum spaces of buildings. In the United States, plastics used in the construction of plenum cable are regulated under the National Fire Protection Association standard NFPA 90A: Standard for the Installation of Air Conditioning and Ventilating Systems. All materials intended for use on wire and cables to be placed in plenum spaces are designed to meet rigorous fire safety test standards in accordance with NFPA 262 and outlined in NFPA 90A. Plenum cable is required because, if nonplenum cable catches fire, it can release toxic fumes. If those fumes are released in a plenum space, they can spread throughout the building through the air circulation system. Plenum cable is jacketed with a fire-retardant plastic jacket of either a low-smoke polyvinyl chloride (PVC) or a fluorinated ethylene polymer ( FEP). Polyolefin formulations, specifically based on polyethylene compounding had been developed by at least two compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messenger Wire
An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, electric multiple units, trolleybuses or trams. The generic term used by the International Union of Railways for the technology is ''overhead line''. It is known variously as overhead catenary, overhead contact line (OCL), overhead contact system (OCS), overhead equipment (OHE), overhead line equipment (OLE or OHLE), overhead lines (OHL), overhead wiring (OHW), traction wire, and trolley wire. An overhead line consists of one or more wires (or rails, particularly in tunnels) situated over rail tracks, raised to a high electrical potential by connection to feeder stations at regularly spaced intervals along the track. The feeder stations are usually fed from a high-voltage electrical grid. Overview Electric trains that collect their current from overhead lines use a device such as a pantograph, bow collector or trolley pole. It presses against the undersid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Digital Interface
Serial digital interface (SDI) is a family of digital video Interface (computing), interfaces first standardized by SMPTE (The Society of Motion Picture and Television Engineers) in 1989. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for Broadcasting, broadcast-grade video. A related standard, known as high-definition serial digital interface (HD-SDI), is standardized in SMPTE 292M; this provides a nominal data rate of 1.485 Gbit/s. Additional SDI standards have been introduced to support increasing video resolutions (High definition video, HD, Ultra high definition, UHD and beyond), High frame rate, frame rates, 3D video, stereoscopic (3D) video, and color depth. Dual link HD-SDI consists of a pair of SMPTE 292M links, standardized by SMPTE 372M in 1998; this provides a nominal 2.970 Gbit/s interface used in applications (such as digital cinema or HDTV 1080P) that require greater fidelity and resolution than standard HDTV can provide. 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a native metal. This led to very early human use in several regions, from . Thousands of years later, it was the first metal to be smelted from sulfide ores, ; the first metal to be cast into a shape in a mold, ; and the first metal to be purposely alloyed with another metal, tin, to create bronze, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
