It seems that up to the 1930's the lead-in feed between antennas and the equipment was parallel wires, with spreaders and binding posts. When the first RF coaxial cable was marketed the UHF connectors PL259 were introduced. You are no doubt aware that the impedance of the coax is determined by the ratio of the inner and outer diameters with a correction factor for the type of dielectric. This calculation we are told gives the impedance of most PL259's as near 30 ohms, not so flash on a 50 ohm cable!
During WW2 Radar required a better connector and two designs followed. The first attempted to make a connector look like a piece of 50 ohm cable, this was designed by Mr. Paul Neill at the at the Bell Laboratories and know as the type N connector. A Carl Concelman however noticed that there was a small bit of inductance where the center pins of the N connector meet. By changing the position of the dielectric used to fill the connector he was able to introduce some reactive cancellation and this type C connector allows it to be used well into the Gegahertz.
Shortly after this, Neill and Concelman cooperated on the design of a miniature bayonet locking connector. This combined Neill's mechanical design with Concelman's reactive dielectric and his twist on locking ring. The Bayonet Neill Concelman (BNC) connector had arrived. Because of the noise generated by the BNC connectors under extreme vibration, Neill and Concelman worked on a threaded version. The Threaded Neill Concelman (TNC) was developed in the late 1950's.
This is a great piece of fun in the form of a shockwave animation showing Ludvig Van Beethoven playing in morse code. This didn't originate here, but it's too fun to let slip away.