75 Ohm SMB Mini Jack for RG-179/187 — Kit Form
The 75 Ohm impedance and SMB snap-on coupling distinguish it from the more common 50 Ohm SMB variants; it is sized for RG-179 and RG-187 coaxial cables, which are typical in video, broadcast, and broadband data applications where 75 Ohm characteristic impedance is the standard.
What the 75 Ohm Rating Means for Signal Path Design
A 50 Ohm SMB jack like the 142138 will not maintain the correct impedance match on a 75 Ohm cable run, causing signal reflections and insertion loss penalties. The 142191-75 is the correct choice when the system impedance is 75 Ohm; the connector style is SMB mini, which is physically smaller than a BNC but uses the same snap-on bayonet-style coupling for quick matings. Insertion loss is rated at 0.3 dB, which is typical for a well-matched SMB interface at lower frequencies.
Kit Contents and Cable Termination
The kit includes six pieces: the SMB connector body, one crimp-style center contact, a crimp ferrule, a section of heat shrink tubing, a lockwasher, and a bulkhead mounting nut. The contact and shield termination are both crimp-style for RG-179 and RG-187 cables.