RG-6
Encyclopedia
RG-6/U is a common type of coaxial cable
used in a wide variety of residential and commercial applications. The term "RG-6" itself is quite generic and refers to a wide variety of cable designs, which differ from one another in shielding characteristics, center conductor composition, and dielectric type. "RG" was originally a unit indicator ("Radio Guide") 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 indicator is no longer part of the JETDS system (MIL-STD-196E) and cable sold today under the RG-6 label does not necessarily meet military specifications. In practice, the term "RG-6" is generally used to refer to coaxial cables with an 18 AWG
center conductor and 75 ohm
characteristic impedance
. RG-6 is insulated with an aluminum foil sheath. Even though RG-59 looks similar to RG-6, RG-59 is insulated with a copper foil sheath.
(CATV) distribution coax, used to route cable television signals to and within homes, and RG-6 type cables have become the standard for CATV, mostly replacing the smaller RG-59
, in recent years. CATV distribution coax typically has a copper-coated steel center conductor and a combination aluminum foil/aluminum braid shield, typically with low coverage (about 60%). RG-6 type cables are also used in professional video applications, carrying either base band analog video signals or serial digital interface
(SDI) signals; in these applications, the center conductor is ordinarily solid copper, the shielding is much heavier (typically aluminum foil/95% copper
braid), and tolerances are more tightly controlled, to improve impedance stability.
at each end; in CATV distribution applications, these are typically F connector
style; in professional base band video, BNC connector
s; and in consumer a/v applications other than RF
and CATV, RCA plugs
.
from a utility pole. "Plenum
" wire comes with a special Teflon outer jacket designed for use in ventilation ducts to meet fire codes.
Coaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
used in a wide variety of residential and commercial applications. The term "RG-6" itself is quite generic and refers to a wide variety of cable designs, which differ from one another in shielding characteristics, center conductor composition, and dielectric type. "RG" was originally a unit indicator ("Radio Guide") for bulk radio frequency (RF) cable in the U.S. military's Joint Electronics Type Designation System
Joint Electronics Type Designation System
The Joint Electronics Type Designation System , which was previously known as the Joint Army-Navy Nomenclature System and the Joint Communications-Electronics Nomenclature System, is a method developed by the U.S. War Department during World War II for assigning an unclassified designator to...
. The suffix "/U" means “for general utility use.” The number was assigned sequentially. The "RG" unit indicator is no longer part of the JETDS system (MIL-STD-196E) and cable sold today under the RG-6 label does not necessarily meet military specifications. In practice, the term "RG-6" is generally used to refer to coaxial cables with an 18 AWG
American wire gauge
American wire gauge , also known as the Brown & Sharpe wire gauge, is a standardized wire gauge system used since 1857 predominantly in the United States and Canada for the diameters of round, solid, nonferrous, electrically conducting wire...
center conductor and 75 ohm
Ohm
The ohm is the SI unit of electrical resistance, named after German physicist Georg Simon Ohm.- Definition :The ohm is defined as a resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere,...
characteristic impedance
Characteristic impedance
The characteristic impedance or surge impedance of a uniform transmission line, usually written Z_0, is the ratio of the amplitudes of a single pair of voltage and current waves propagating along the line in the absence of reflections. The SI unit of characteristic impedance is the ohm...
. RG-6 is insulated with an aluminum foil sheath. Even though RG-59 looks similar to RG-6, RG-59 is insulated with a copper foil sheath.
Applications
The most commonly recognized variety of RG-6 is cable televisionCable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
(CATV) distribution coax, used to route cable television signals to and within homes, and RG-6 type cables have become the standard for CATV, mostly replacing the smaller RG-59
RG-59
RG-59/U is a specific type of coaxial cable, often used for low-power video and RF signal connections. The cable has a characteristic impedance of 75 ohms. The 75 ohm impedance matches a dipole antenna in free space. "RG" was originally a unit indicator for bulk radio frequency cable in the...
, in recent years. CATV distribution coax typically has a copper-coated steel center conductor and a combination aluminum foil/aluminum braid shield, typically with low coverage (about 60%). RG-6 type cables are also used in professional video applications, carrying either base band analog video signals or serial digital interface
Serial Digital Interface
Serial digital interface is a family of video interfaces standardized by SMPTE. For example, ITU-R BT.656 and SMPTE 259M define digital video interfaces used for broadcast-grade video...
(SDI) signals; in these applications, the center conductor is ordinarily solid copper, the shielding is much heavier (typically aluminum foil/95% copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
braid), and tolerances are more tightly controlled, to improve impedance stability.
Connectors
RG-6 cables typically are fitted with various types of connectorRF connector
A coaxial RF 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...
at each end; in CATV distribution applications, these are typically F connector
F connector
The F connector is a type of coaxial RF connector commonly used for "over the air" terrestrial television, cable television and universally for satellite television and cable modems, usually with RG-6/U cable or, in older installations, with RG-59/U cable. It was invented by Eric E...
style; in professional base band video, BNC connector
BNC connector
The BNC connector ' is a common type of RF connector used for coaxial cable. It is used with radio, television, and other radio-frequency electronic equipment, test instruments, video signals, and was once a popular computer network connector. BNC connectors are made to match the characteristic...
s; and in consumer a/v applications other than RF
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
and CATV, RCA plugs
RCA connector
An RCA connector, sometimes called a phono connector or cinch connector, is a type of electrical connector commonly used to carry audio and video signals...
.
Types
RG/6 is available in three different types designed for various applications. "Plain" or "house" wire is designed for indoor or external house wiring. "Flooded" cable is infused with heavy waterproofing for use in underground conduit (ideally) or direct burial. "Messenger" or "Aerial" may contain some waterproofing but is distinguished by the addition of a steel messenger wire along its length to carry the tension involved in an aerial dropDrop (telecommunication)
Drop, in telecommunication, has several meanings.* 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...
from a utility pole. "Plenum
Plenum cable
Plenum cable is cable that is laid in the plenum spaces of buildings. The plenum is the space that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows...
" wire comes with a special Teflon outer jacket designed for use in ventilation ducts to meet fire codes.