Where I am, there are only two kinds: RG-59U and RG-6U. RG-59 is the older and thinner of the two (very roughly a quarter of an inch in diameter). RG-6 is newer and fatter.
RG-59U uses a old style F connector that slides on and has a barrel that is crimped to connect the shield of the cable to the metal F connecter. The coax center conductor is the plug.
I have only ever seen RG-6U put on by cable technicians (it is their cable). They use a more professional connector that has its own plug. The cable is prepared, inserted and crimped with a heavier duty crimper.
First figure out what you have: thin = RG-59U, fat = RG-6U
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