So let's run the numbers on a PL-259 connector and SO-238 socket. Unfortunately they omitted the "D" dimension on the above drawing but we can guesstimate a little.
Characteristic impedance Zo = 138 Log (12/5.5) = approximately 47Ω. Granted, if it is a little bigger say 6.0mm then it's is approximately 42Ω.
Back when I was a repair technician for a Motorola Service Shop, Motorola produced an 800 MHz radio that had an SO-238 antenna connector! I couldn't believe it but it worked and now I know why.