Earth Station - The term used to describe the combination of antenna, low-noise amplifier (LNA), down-converter, and receiver electronics that are used to receive a signal transmitted by a satellite.

EBCDIC - This acronym stands for Extended Binary-Coded Decimal Interchange Code, and it is, similar to ASCII, a way of coding characters.

Echo Canceller - An electronic circuit which eliminates or attenuates the echo effect on satellite signals.

Echo Effect - A time-delayed electronic reflection of a sound that can be eliminated by echo cancellers.

Edge of Coverage (EOC) - A satellite's defined service area.

Edit - To change the content of a file.

Editor - This is piece of software that allows you to edit a file.

EIRP - This stands for Effective Isotropic Radiated Power. This term expresses the strength of the signal leaving the satellite or transmitting earth station antenna.

Electromagnetic Force - This is one of the four forces (with the other three being gravity and the strong and weak nuclear forces), and it has an infinite range and acts between objects according to their charge. It is proportional to the strength of the charges and inversely proportional to the square of the distance between them.

Electromagnetic Spectrum - This is the full range of frequencies, from radio waves to gamma rays, that characterizes light, and there is a direct relationship between the amount of energy electromagnetic radiation carries and its frequency. Radio waves are at one end of the spectrum and are low frequency and low energy radiation, while gamma rays are at the other end of the spectrum and are high frequency and high energy radiation. Visible light falls somewhat near the middle of the spectrum.

Electronic Mail - See Email.

Elevation - The measurement of the tilt of a satellite antenna, measured in degrees, that is required to point the antenna at the communications satellite. If, for example, the antenna were aimed at the horizon, the elevation angle would be zero (directly overhead would be 90 degrees).

Email - This is electronic-mail, that is text messages that are sent over the internet.

Emoticons - This is a contraction meaning emotional icon that is made with common characters, such as :-) being made from :, -, and ).

Emulate - This is when a copy of a system is made (i.e., a duplication).

Encoder - A device that is utilized to alter a signal electronically so that it can only be viewed with a receiver equipped with a decoder.

Encryption - This is when data is put into a coded form for protection, and only those with the proper access information (i.e., the encryption code) can see the data.

EOC - see Edge of Coverage.

EOF - This is the acronym for End Of File.

Equatorial Orbit - An orbit that is parallel to the earth's equator.

Error - This is any sort of general incorrect or unwanted procedure or piece of data.

Error Control - This is the same quality control, and it involves checking the reliability of received data.

Escape Sequence - This is a sequence of characters that is meant to be read as an escape command.