TNC Jack for LMR-400 — 8 GHz, 50 Ohm, Panel Mount
The Amphenol RF 031-6874 is a TNC jack, female socket, from the ARC series — a threaded RF interface that mates with a standard TNC plug. This is a single-port, bulkhead-mount design secured by a front-side nut, intended for fixed installations where the connector stays panel-mounted and the cable is terminated in the field.
What the 8 GHz and 500-Cycle Ratings Mean for Field Use
The 8 GHz maximum frequency covers the L-band through C-band, so this jack handles GPS, Wi-Fi, cellular backhaul, and ISM-band applications without hitting the interface's roll-off. The 500 mating cycles are a direct result of the gold-plated center contact — tin or silver would fret sooner under the threaded coupling nut's torque. For a panel-mount bulkhead connector that gets mated a few times during installation and then left alone, 500 cycles is generous headroom.
Termination and Mounting Sequence
The shield is crimped to the LMR-400 braid, and the center conductor is soldered into the contact. The bulkhead mount uses a front-side nut that tightens against the panel from the outside — the connector body does not rotate during cable termination, which keeps the center contact aligned. The threaded fastening type means the mating plug screws on, not push-and-twist like a BNC, so vibration or cable tug will not unseat the pair.