The 1-221185-0: The nickel-plated body and gold-plated brass center contact suit it for video distribution, CCTV, and telecom infrastructure where 75 Ohm impedance is standard — think broadcast video routers, head-end equipment, or base station monitoring links. The polyethylene dielectric keeps insertion loss to 0.15 dB at rated frequency.
If your system is built around 50 Ohm coax (common for RF test gear, radio, or cellular), this connector will introduce a mismatch and degrade return loss. Stick with 75 Ohm cable like Belden 9145 (RG-59 type) to keep the impedance through the interconnect clean. The 2 GHz bandwidth covers standard-def and HD-SDI video (up to 3 GHz for 3G-SDI is a stretch, but 1.5 GHz HD-SDI is within range).
Termination and Cable Match
The shield termination is crimp, not clamp, so you need the correct hex die for the ferrule size that matches Belden 9145. The gold-plated center contact crimps onto the signal conductor; the nickel body handles the shield ground. If you're swapping cable types, the body geometry is tuned for the 9145 jacket diameter — a different cable group may not seat the ferrule correctly.
If you're designing a new build, look for a current-production 75 Ohm BNC plug from TE's standard catalog that matches your cable group and impedance.