The TNC connector or (Threaded Neill -Concelman) is a slightly smaller RF connector. Similar to the more common BNC, but with a threaded coupling instead of a bayonet coupling. TNC connectors have a 7-16-28 UNEF thread. Impedance is generally 50. However, there are a few 75 Ω on the market. The TNC connector typically operates in the DC-11 GHz frequency range.
TNC connectors are often likely to be used in applications where the connector needs to survive vibration, and provide reliable performance at high frequencies and the convenience of the bayonet connection is not required.