Help needed identifying an RF connector in old HP equipment

[TERRA Operative]

I have an old HP 5340A Frequency Counter here that I am attempting to rescue.

I found a missing interconnect cable amongst the many horrors and I just need some help in identifying the connector.
The other end of the cable is a SMB female, but can anyone tell me what connector type connects to the one shown in the attached pic?

The diameter of the smooth part is 3.75mm

[ConKbot]

Looks like SMC. I'm finding specs online for 3.6-3.7mm for the smooth OD of the jack barrel of it, so its close.

[ArthurDent]

I'd say SMC as well.

[TERRA Operative]

Yeah, looks like you guys are right.
It matches up with what I've found too.

Thanks!