Female to female coupler (also known as barrel connectors) are used to convert a male plug to a female. We do not recommend Female Co Ax sockets (except right angle types) because the design of them is not conducive to reliability. Very few trade aerial suppliers sell them either, and that`s got to tell you something.
Connector shown both ways in the picture, obviously only one (or five) is supplied !
Also see F connector Back to Back