The tnc connector is a threaded version of the bnc connector the connector has a 50 ohm impedance and operates best in the 0–11 ghz frequency spectrum.the tnc series connector was originally designed offering threaded coupling nut mating in lieu of the popular bnc bayonet-type coupling. Tnc connectors offered superior electrical performance, higher frequency range, and the ability to withstand severe shock and vibration requirements.