Glossary - F

Feed
1: assembly at the focus of a reflector antenna, usually consisting of a feed horn and often other equipment such as an OMT and part of the tracking system (particularly in larger antennas)
(technology)

Feed
2: transmission of video signals from a distribution centre
(broadcasting)

Feeder link
a transmission in the FSS band which will ultimately be retransmitted by another service, for example by the broadcasting satellite service
(regulation, satellite communications)

Feedhorn
a horn antenna normally placed at the focus of a parabolic antenna to radiate or collect RF signals
(technology)

Filter
a device that allows only a predetermined range of frequencies to pass through
(technology)

Finger
an individual digital channel of a rake receiver; also called a tine
(technology)

Fixed Assignment TDMA (FA-TDMA)
is a synchronised variant of TDMA in which transmissions only occur in exclusively allocated time slots
(communications)

Fixed Satellite Service
the satellite radiocommunications service between fixed earth stations on the earth's surface
(regulations)

Flat panel antenna
a type of low profile antenna than uses a phased array of small antenna elements
(technology)

Flatsat
a testbed for a small satellite (usually a CubeSat) in which all of the internal modules of the spacecraft are laid out on a table or a flat plate, and are connected together as they would be in flight to test the functionality of the electronics
(technology)

Fluorescence
the emission of light by a substance following the absorption of light of a nonvisible frequency
(physics)

Fly-away terminal
transportable terminal designed to be packed into several containers which can be shipped by commercial airliner
(satellite communications)

Footprint
1: the area on the Earth in which a satellite's signals can be received
(satellite communications)

Footprint
2: the contour map of received signal strength from a satellite
(satellite communications)

Frequency coordination
the process by which the frequencies and power levels assigned to a satellite or earth station are chosen to reduce interference with other satellites to an acceptable level
(regulation)

Frequency Division Multiple Access (FDMA)
a technique in which several earth stations share a repeater by transmitting simultaneously at different frequencies
(communications)

Frequency reuse
the technique of using the same frequency simultaneously in a system for more than one transmission, for example in different beams from a satellite
(satellite communications)