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.
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
3 Flex F connectors
5 See also
7 Further reading
8 External links
F connector is inexpensive, gendered, threaded, compression
connectors for radio frequency signals. It has good 75 Ω
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 center conductor and
external threads. The male connector has a center 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
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.
Female connectors are typically used 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 center sockets and
dielectric, entirely at the factory where tolerances can easily be
This design is subject to the surface properties of the inner
conductor (which must be solid wire, not stranded) and is not
corrosion resistant. Hence waterproof versions are needed for outside
use (for example, on antennas). Corrosion resistance can be improved
by coating all bare copper wires with silicone grease.
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 an o-ring (of about 7 mm)
inside the captive nut. This seals between the mating faces of both
connectors, providing good waterproofing for the center conductor.
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
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[clarification needed] 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
F connectors attached to a 4-way
A visual collection of standard and right-angle coaxial F connectors,
a commonly used but less documented form of the F connector.
Radio frequency coaxial connectors with screw coupling, typically
for use in 75 ohm cable networks (type F)
TV aerial plug
^ Electrical Connector. US Patent 3,537,065 by Eric Winston
^ IEC 60169-24: "Radio-frequency connectors - Part 24: Sectional
Radio frequency coaxial connectors with screw
coupling, typically for use in 75 Ω cable networks (type F)." (2009)
^ "Understanding lnb specifications" (PDF). SatCritics Technicals.
2002-11-15. Retrieved 2017-11-29.
^ "How to wire a Belling-Lee connector". www.megalithia.com.
^ Cityfreq United States Scanner Frequencies, Phone Numbers, and IP
"F" Port (Female Indoor) Physical Dimensions, ANSI/SCTE 02 2015 (see
Compression Tool for crimping
RF connectors (coaxial)
TV aerial plug
UHF / Mini-UHF
Variations and alternate names
2.9 mm (SMA)
Triax / Triaxial
Twin BNC / Twinax (BNC)
Old or seldom used
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