BNC Coaxial Cable Connector T-Junction Male To 2 Female Adaptor For RG59 Wiring

Types of BNC Connectors The BNC (Bayonet Neill–Concelman) connector is a miniature quick connect / disconnect radio frequency connector used for coaxial cable. It features two bayonet lugs on the female connector; mating is fully achieved with a quarter turn of the coupling nut. BNC connectors are most commonly made in 50 ohm and 75 ohm versions, matched for use with cables of the same characteristic impedance. The 75 ohm connector is dimensionally slightly different from the 50 ohm variant, but the two nevertheless can be made to mate.

The 75 ohm types can sometimes be recognized by the reduced or absent dielectric in the mating ends but this is by no means reliable. There was a proposal in the early 1970s for the dielectric material to be coloured red in 75 ohm connectors, and while this is occasionally implemented, it did not become standard. The 75 ohm connectors are typically specified for use at frequencies up to 2 GHz. 75 ohm BNC connectors are primarily used in Video (particularly HD video signals) and DS3 Telco central office applications. Many VHF receivers use 75 ohm antenna inputs, so they often used 75 ohm BNC connectors.

The 50 ohm connectors are typically specified for use at frequencies up to 4 GHz. 50 ohm connectors are used for data and RF. A 95 ohm variant is used within the aerospace sector, but rarely elsewhere. It is used with the 95 ohm video connections for glass cockpit displays on some aircraft. Compatibility The different versions are designed to mate with each other, and a 75 ohm and a 50 ohm BNC connector which both comply with the 1978 standard, IEC 169-8, will mate non-destructively. At least one manufacturer claims very high reliability for the connector’s compatibility. At frequencies below 10 MHz the impedance mismatch between a 50 ohm connector or cable and a 75 ohm one has negligible effects. BNC connectors were thus originally made only in 50 ohm versions, for use with any impedance of cable. Above this frequency, however, the mismatch becomes progressively more significant and can lead to signal reflections.