Fade - This is a reduction in the received signal. It is caused by absorption, refraction, or reflection.

Fax - This is a shortening of Facsimile, and it refers to one fax machine sending a digital representation of a hardcopy over the phone lines to be received and printed out by another fax machine.

FCC - see Federal Communications Commission

F/D - the ratio of antenna's focal length to the antenna's diameter. If there is a greater F/D it means there is a shallower dish.

FDM - see Frequency Division Multiplexing.

Feature - This term refers to any of the tasks that a particular piece of equipment can perform or carry out.

Feed - this (1) describes the physical feed system of the antenna, and (2) describes the actual signal transmission of the data or information from the distributors.

Feedback - This occurs when part of the output signal returns to the input side of the electronic device.

Federal Communications Commission (FCC) - This is the government agency that regulates all interstate communications that originate within the United States. The FCC has no intrastate authority.

Field - This refers to the particular location of a piece of data within a record (which is within a file of a database).

File - This term refers to any intended collection of data with similar characteristics. A file could be anything from a document to a component of a computer program.

Filter - This is a device which allows a particular spectrum (range of frequencies) to pass through it but prohibits (attenuates) all others from passing.

Firewall - This is a system of both software and hardware, and it has purpose of limiting the vulnerability of a computer or set of computers from outside attack (i.e., hacking).

Flash - This is a function on a telephone or other phone device that rapidly hangs-up and reconnects the telephone line.

Flag - In programming, this is a variable that is used to relay when a particular condition of the program has been met.

Flow Control - This is a method of controlling the transfer of information (messages, characters, etc.) between a network's data points.

Focal Length - Distance from the exact center of the dish to the center of the feed.

Focal Point - The physical point in space toward which the satellite reflector dish directs the received signal so it can be processed.

Format - This is (1) the general makeup and organization of a file, or (2) the arrangement of bits of characters within a group.

Forum - This is a section of a website or online service, wherein you can communicate with other forum members about a common subject.

Forward - This is the act of redirecting a particular email, an entire email address, or a telephone number.

Forward Error Correction (FEC) - The purpose of this element is to add unique codes to the digital signal at the output source so problems can be detected at the signal receiver.

Freeware - This is software that is free to use and distribute. Some freeware, though, requires that you don't make any changes or alterations to the code.

Frequency - The number of times that a wave or wave-like process goes through its complete cycle per second of time. Frequency is measured in hertz (Hz), which is one cycle per second.

Frequency Band - This is a particular band of frequencies in the electromagnetic spectrum, expressed in Hertz, in which satellite signals are transmitted.

Frequency Coordination - A process that is implemented to attenuate frequency interference between different satellite networks.