BNC (Bayonet Neill-Concelman) connectors are RF connector types that are used for BNC cable that connect several television, radio and other frequency tools. BNC cables use small needles that are similar to needles of coaxial cables. The needle is surrounded by a cylindrical casing which is in turn surrounded by metal pieces. These cables connect by twisting and attaching in the cable. And they can be used to make reliable connections as they easily adapt to numerous outputs and inputs.
The BNC cables are named after its mechanism that is bayonet locking and also after its inventors. They exist in 75 ohm and 50 ohm versions and they can be used along with other cables that have similar characteristic impedance. These cables are specifically designed to be used with frequencies of up to 2 and 4 GHz respectively. BNC cables of 75 ohm can be recognized the absent or reduced dielectric at the mating ends. These are commonly used for DS3 and video office applications while the 50 ohm BNC cables are usually used for RF and date. Many VHF antenna outputs used the 75 ohm.
BNC Cable Connector Compatibility
Although there are different versions of the BNC cables, both the 50 ohm and 75 ohm connectors will effectively comply with a standard IEC 169-8 and mate non-destructively. In fact, there are manufacturers that claim that these cables are very reliable when it comes to connection compatibility. When it comes to electrical compatibility, the 75 ohm and 50 ohm cables impedance mismatch, especially when using under 10 MHz. Thus, originally, the BNC cables were made only as the 50 ohm. This is because such could be used with almost all cable impedance. With frequencies going over 50 ohm, the impedance mismatch becomes more and more significant which can lead to signal reflections.
BNC Cable Tools
There are special tools which are used when inserting or removing the BNC cables into or from hard to reach or high density locations like patch panels that are heavily wired like those used by broadcast facilities for security purposes. Although BNC cables are largely used in various electronics, there are some miniature connectors that are slowly replacing their use. The miniature tools are slowly gained popularity over the BNC cables because they allow higher density uses.
Other cables that can be used to serve the same purpose as the BNC cables include SR-75 and SR 50 cables, TNC cables, twinax and triaxial cables. The TNC cables are a threaded alternative to BNC. These cables provide for a superior performance at microwave frequencies when compared to BNC. The twinax cables use the same bayonet like standard BNC cables but they contain 2(male and female) independent points thus allowing for connection of a 96 ohm or 78 ohm. These cables cannot mate with the normal BNC cables. The triaxial cables carry both signals while at the same time guarding as a conductor. For these reasons, they are used in electronic systems that are sensitive. The latest designs of triaxial cables are three-plug to ensure that there is no accidental mating with any standard BNC Cable.