The F connector (also F-type) is a coaxial RF connector commonly used for "over the air" terrestrial television, cable television and universally for satellite television and cable modems, usually with RG-6/U cable or, in older installations, with RG-59/U cable.
The F connector was invented by Eric E. Winston in the early 1950s while working for Jerrold Electronics on their development of cable television. In the 1970s, it became commonplace on VHF, and later UHF, television antenna connections in the United States, as coaxial cables replaced twin-lead.
It is now specified in IEC 60169 Radio-frequency connectors, part 24.
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Description
The F connector is inexpensive, gendered, threaded, compression connectors for radio frequency signals. It has good 75 ? impedance match for frequencies well over 1 GHz and has usable bandwidth up to several GHz.
Connectors mate using a 3/8 in-32 unified extra fine (UNEF) thread. The female connector has a socket for the central conductor and external threads. The male connector has a central pin, and a captive nut with internal threads.
The design allows for low-cost construction, where cables are terminated almost exclusively with male connectors. The coaxial cable central conductor directly 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 need to have tight tolerances. Push-on versions are also available.
Female connectors mostly occur on bulkheads or as couplers, often being secured with the same threads as for the connectors. Thus can be manufactured as a single piece, with central sockets and dielectric, entirely at the factory where tolerances can easily be controlled.
This design is subject to the surface properties of the inner conductor (which must be solid wire) and is not corrosion resistant; hence waterproof versions are needed for outside use (for example, on aerials). Corrosion resistance can be improved by coating all bare copper wires with silicone grease.
Weatherproof
The F connector is not weatherproof; neither the threads nor the joint between male connector body and captive nut seal. However, male connectors are commonly enhanced with a o-ring (of about 7 mm) inside the captive nut; this seals between the mating faces of both connectors, providing good waterproofing to the central conductor.
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Usage
The cable and satellite television entities (as a near standard practice) use compression fittings with F connectors on customer premises. In Europe, block down-converted satellite signals (950-2150 MHz) from LNBs and DC power and block signalling from satellite receivers are near exclusively passed through F connectors.
F connectors are probably the most suitable for domestic terrestrial, cable, and satellite TV installations where the delivery of very high frequency information is required. Belling-Lee connectors (IEC 169-2; used on European terrestrial receivers) are not well suited for long-haul building delivery of frequencies above 500 MHz, because the standard was designed around tube receivers and mediumwave (or shortwave) antennas (but workarounds exist). F connectors require slightly more care to properly install the male connectors to the cable than the Belling-Lee type, with the exception of compression or flex type connections.
Flex F connectors
Push-on (aka Flex) F connectors provide poorer shielding against microwave signals of high field strength. This leakage problem is more an artifact of bent or partly broken push on connectors, but is mostly not observed with compression connectors. Nearby television, FM radio, mobile & cordless phones, government radiolocation (54-1,002 MHz) transmitters can potentially interfere with a CATV or DTH Satellite reception or operation if the Flex connector poorly installed.
Source of the article : Wikipedia
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