The 36650-3RFX: The 500 mating cycle rating means it handles regular reconnection without the contact wear you would see on a cheaper tin-plated BNC — the gold-plated centre contact and nickel body finish are what let it hold consistent performance through those cycles. This is a crimp-termination plug, which gives a more consistent shield termination and pull-off strength than a clamp-style BNC. The shield is crimped through the ferrule; the centre contact is crimped separately.
Cable selection and termination
The 36650-3RFX is sized for RG-58 plenum, Belden 88240, Belden 89907, and 122-type cables. The crimp dimensions inside the ferrule and centre contact are specific to that cable group — using a different coax diameter will give a poor shield crimp and shift the impedance at the junction. Stick to the listed cable types for a 50 Ohm match through the connector.
No official replacement or cross-reference exists for this part. If you are matching a BOM line, confirm the cable group and the 50 Ohm impedance match your system before committing.