75 Ohm BNC Barrel Coupler — TE Greenpar 1-1478043-0
The TE Connectivity 1-1478043-0 is a straight BNC to BNC adapter from the Greenpar series, configured as a plug-to-plug barrel with male center contacts on both ends. It carries a 75 Ohm characteristic impedance — the standard for broadcast video, CCTV, and baseband digital video signal paths — not the 50 Ohm used in RF test equipment or telecom. The adapter is rated to 2 GHz maximum frequency, covering the full SDI and HD-SDI bandwidth with margin.
Impedance and Signal Path — Why 75 Ohm Matters
The 75 Ohm impedance is the defining spec on this adapter. A 75 Ohm BNC has a different center pin diameter and dielectric geometry than a 50 Ohm BNC — they are mechanically incompatible. Plugging a 75 Ohm adapter into a 50 Ohm system creates a reflection at the junction that degrades signal integrity above a few hundred MHz. This adapter is built for 75 Ohm paths: composite video, serial digital interface (SDI) at 270 Mbps to 3 Gbps, and baseband analog video. The PTFE dielectric keeps the impedance stable across temperature and frequency, and the silver plating on the contacts and body maintains low insertion loss through the 2 GHz band.
Mating Cycles and Field Service
Rated for 500 mating cycles, this adapter is designed for patch-panel and test-bench use where connectors get connected and disconnected regularly. The silver-plated brass contacts resist oxidation and maintain contact resistance over those cycles better than unplated brass. The free-hanging (in-line) mounting style and bayonet lock on both ends mean it can be used as a barrel coupler between two cable-mounted BNC plugs without any panel cutout — just spin the knurled body and the bayonet slots engage. The body finish is silver, matching the standard BNC aesthetic for broadcast racks.