TNC

TNC connectors are a screw lock coupling version of the BNC connectors. The screw coupling enables TNC to be used at frequencies up to 11GHz in harsh environment situations. Widely used for antenna connections, TNC have many applications in avionics, defence, communications and general industrial markets. Reverse polarity, 50 ohm and 75 ohm TNC connectors are available.

For details; http://www.coax-connectors.com/products/connectors/tnc.aspx