The connector has a 50 Ω impedance and operates best in the 0–11 GHz frequency spectrum. It has better performance than the BNC connector at microwave frequencies. Invented in the late 1950s and named after Paul Neill of Bell Labs and Carl Concelman of Amphenol, the TNC connector has been employed in a wide range of radio and wired applications.
The TNC connector was developed to overcome one of the major shortcomings - that of variations in resistance and connection with the outer sleeve during vibration. As the bayonet fixing moved slightly there were small variations in resistance that gave rise to noise. It overcame this issue by having a much firmer screw or threaded arrangement for the outer part of the connector.In Its name from the threaded arrangement used: Threaded Neill Concelman.
TNC connectors are not only plugs and sockets, they are also adapters and other items such as attenuators - in other words they come in a variety of formats.
TNC plugs are designed not only for the required impedance, but also to accept a particular coaxial cable format. In this way all the internal piece parts are compatible with the coaxial cable used. It is therefore necessary to specify the TNC plug for use the cable to be used. Although there is some latitude, it is naturally best to select the correct cable format.
In addition to this there are straight and right angled variants. Of these the straight connectors are the most widely used, although right angled connectors where the cable leaves the plug at right angles to the centre of the connector centre line are also available. These are ideal in many applications where the cables need to leave the connector in this manner to ensure cables are in a tidy fashion, or where space is at a premium. Unfortunately right-angled connectors have a marginally higher level of loss than their straight through counterparts. This may not be significant for most applications, but at frequencies near the operational limit of the connector there may be a small difference