What is a BNC Cable And What does BNC Stand for?

BNC Cable Assembly

A common type of coaxial cable assembly used throughout the RF industry is a BNC cable, or BNC coaxial cable assembly. A BNC cable is used for signal routing below roughly 4 GHz (there are high precision BNC connectors that reach maximum frequencies to 12 GHz or beyond). BNC stands for Bayonet Neill–Concelman, and is a miniature quick connect/disconnect style RF coaxial connector. A BNC cable is a coaxial cable that has BNC connectors on either end. This type of cable is used to route signals from test equipment or devices that have BNC coaxial connector ports, where the ports are typically RF female connectors, and the BNC connectors are RF male connectors. Though, there are BNC connectors with reverse polarity, or reverse polarity BNC (RP-BNC).

These connector and cable styles are used as mating between a male and female connector is done by inserting the RF male connector into the female port  using the alignment guides (lugs) and applying a relatively small amount of force to turn the male connector bayonet structure a quarter turn. Given the wide use of BNC cables, these cables also often come with a single BNC connector side and the other coaxial side in a different connector type or interface, such as 10-32, alligator, banana, BNC, FME, GR874, hook, mini alligator, mini banana, MMCX, N, NMO Mount, SMA, SMB, SMC, Tip, TNC, UHF or unterminated leads used for direct soldering, clamping, etc. These cables are typically made in either 50-ohm varieties or 75-ohm varieties. The nominal impedance of these cables depends on the application, where broadcast, audio/visual, and low frequency communications may use 75 ohms, most RF applications use 50 ohms. BNC cable assemblies were also used widely in early computer and electronics networking equipment and also for a range of analog/digital interfacing and signal routing.

Both 75 ohm and 50 ohm BNC cables can mate non-destructively per the 2007 IEC standard, IEC 61169-8. This type of mating is only recommended for very low frequencies ( < 10 MHz) as the impact of the impedance mismatch at higher frequencies becomes more significant as a function of frequency. BNC cables are generally only used for signal applications and are generally note rated for high voltages or high-power use. However, there are high voltage BNC (HV-BNC) and high-power BNC connector variants available that can be installed on appropriate high voltage and high-power coaxial cable.