coaxial cabling terms
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8/13/2019 Coaxial Cabling Terms
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CoaxialCablingTutoria
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66 Coaxial Cabling Terms
Coaxial Cabling is a two conductor closedtransmission medium that is often used for thetransmission of RF energy. The system offers tightcontrol over electrical impedance. This yieldsexcellent performance at high frequencies andsuperior EMI control/shielding when compared toother types of copper cabling. Coaxial cabling iscommonly found in test environments as well asin broadcast and networking systems. Listed beloware some common terms and definitions that arerelated to coaxial cabling:
Attenuation (Insertion Loss): Loss of power.Attenuation is usually measured in dB loss perlength of cable (ex. 31.0 dB/100Ft.). Attenuationincreases as frequency increases.
BALUN: An acronym for BALanced/UNbalanced.A device commonly used to change one cablingmedia to another (ex. coaxial to twisted pairbalun).
Center Conductor: The solid or stranded wire inthe middle of the coaxial cable. The conductordiameter is measured by the American WireGauge (AWG).
Coaxial Adaptor: A device used to change oneconnector type to another or one gender toanother (ex. BNC to SMA Adaptor).
Coaxial Cable: A two conductor cylindricaltransmission line typically comprised of a centerconductor, an insulating dielectric material and anouter conductor (shielding). Coaxial cable can beflexible (typical to the assemblies found in thiscatalog), semi-rigid or rigid in nature.
Coaxial Connector: The interconnection devicefound at each end of a coaxial cable assembly.There are many common types of coaxialconnectors such as: BNC, SMA, SMB, F, etc.
Dielectric: The insulating material that separatesthe center conductor and the shielding.
Electromagnetic Interference (EMI): Electricalor electro-magnetic energy that disrupts electrical
signals.Frequency: The number of times a periodic actionoccurs in one second. Measured in Hertz.
Impedance: The opposition to the flow ofalternating or varying current.Measured in Ohms.
Jack: The female connector usually containing acenter socket.
Plug: The male connector usually containing acenter pin.
RG/U: Symbols used to represent coaxial cablethat is built to U.S. government specifications(R=Radio Frequency, G=Government,U=Universal Specification).
Shielding: Conductive envelope made of wires ormetal foil that covers the dielectric and the centerconductor.
Twinaxial: An offshoot from coaxial cabling. Twocenter conductors with one dielectric and braidedshielding.
VSWR (Voltage Standing Wave Ratio): Amountof reflected power expressed as a ratio (Ex. 1.25:1)VSWR increases as frequency increases.
Typical Coaxial Cabling (Exploded View):
Typical Coaxial Connector (BNC Exploded View):
Terminating RG58C/U Coaxial Cable with a BNC Plug:
Cut cable to length and slide crimpsleeve onto free end.
Strip free end with Coaxial CableStripper (HT302B,pg. 34).
Slide pin onto center conductormaking sure base of pin meetsdielectric.Crimp with HT230A, pg.35.
Fan braid and s lide plug over pin. Pull cr imp s leeve over braid andferrule.
Crimp and test.
Shielding:
One of the two conductors in coaxialcable. Braid or braid + foil is typical.
Jacket:
Insulates and protects shieldingand center conductor. ExtrudedPVC is typical.
Center Conductor:
The main signal path.Can be solid or stranded wire.
Connector (Plug) Body:
Nickel plated brass is typical.
Center Pin:
Terminates to centerconductor via crimpingor soldering.
Crimp Sleeve:
Provides strain reliefby securing braid to
connector.
Ferrule:
Provides mating surfacefor coaxial shielding.
Dielectric:
Insulating material isolates shield fromcenter conductor.This also gives thecable its impedance property.
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