75 Ohm BNC Bulkhead Adapter for Video and Broadcast Signal Paths
The Amphenol 031-220N-75RFX is a straight BNC jack-to-jack adapter designed for 75 Ohm signal paths, with a 4 GHz frequency ceiling. The 75 Ohm impedance targets video distribution, CCTV, broadcast, and baseband digital video interfaces where the characteristic impedance of the cable (RG59, RG6) and the connector must match to avoid reflections. The adapter mounts through a panel bulkhead, with the nickel-plated brass body providing RF shielding and the gold-plated phosphor bronze center contacts maintaining low and stable contact resistance over repeated bayonet-lock mating cycles.
75 Ohm vs 50 Ohm — The Impedance Decision
The 031-220N-75RFX carries a 75 Ohm impedance, versus the 50 Ohm rating of the otherwise identical-looking 031-220N-50RFX and the 031-4803-RFX. The 75 Ohm interface is standard for video and broadcast equipment; the 50 Ohm version is for RF test, telecom, and wireless infrastructure. Using a 75 Ohm adapter in a 50 Ohm path introduces a 0.5 dB impedance mismatch at the connector interface — acceptable for low-frequency control signals but a problem at the 4 GHz upper band where return loss degrades. The 031-4803-RFX is a 50 Ohm sibling that also includes an isolated mounting feature and a stated 500 mating cycle life.