TNC Coaxial Connector
The TNC (Threaded Neill–Concelman) connector is a threaded version of the BNC connector. The interface specifications for the TNC and many other connectors are referenced in MIL-STD-348. The connector has a 50-ohm impedance and operates best in the 0–11 GHz frequency spectrum. It has better performance than the BNC connector at microwave frequencies.
Most TNC connectors are 50-ohm type even when used with coaxial cable of other impedances, but a 75-ohm series is also available, providing a good SWR to about 1 GHz. These can be recognized by a reduced amount of dielectric in the mating ends.
Reverse-polarity TNC (RP-TNC) connectors have been widely used by Wi-Fi equipment manufacturers to comply with specific local regulations, such as those from the FCC, which are designed to prevent consumers from connecting antennas which exhibit gain and therefore breach compliance. The FCC considered that the RP-TNC was acceptable in preventing consumers from changing the antenna.