The F connector is an inexpensive, gendered, threaded, compression connector for radio frequency signals. It has good 75 Ω impedance match for frequencies well over 1 GHz[2] and has usable bandwidth up to several GHz.
Connectors mate using a 3/8-32UNEF thread. The female connector has a socket for the center conductor and external threads. The male connector has a center pin, and a captive nut with internal threads.[citation needed]
The design allows for low-cost construction, where cables are terminated almost exclusively with male connectors. The coaxial cable center conductor forms the pin, and cable dielectric extends up to the mating face of the connector. Thus, the male connector consists of only a body, which is generally crimped onto or screwed over the cable shielding braid, and a captive nut, neither of which require tight tolerances. Push-on versions are also available.[citation needed]
Female connectors are typically used on bulkheads or as couplers, often being secured with the same threads as for the connectors. They can be manufactured as a single piece, with center sockets and dielectric, entirely at the factory where tolerances can easily be controlled.[citation needed]
This design is sensitive to the surface properties of the inner conductor (which must be solid wire, not stranded).[citation needed]
Weatherproofing
The F connector is not weatherproof. Neither the threads nor the joint between male connector body and captive nut provide a water-tight seal. However, male connectors are commonly enhanced with an o-ring (of about 7 mm) inside the captive nut. This seals between the mating faces of both connectors, providing some protection for the center conductor.[citation needed]
Alternatively, waterproof versions or enclosures are recommended for outside use (for example, on antennas). Corrosion resistance, reliability of connector electrical conduction and water resistance can be improved by coating all bare copper wires and the connectors themselves with silicone grease. [3]