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Telecom Dictionary - G

Gain - This is an increase in signal power, due to a boost from an electronic device.

Garbage - These are unwanted characters that appear because of either incorrect settings or noise.

Gate - These are (1) devices that are used to handle many incoming phone calls, and (2) circuits on silicon chips.

Gateway - This is an entrance into and exit from a network.

Gauge - This is a measurement of the thickness (diameter) of wire or cable.

General Call - A general inquiry call -- the letter CQ in the international code.

GEO - see Geostationary Earth Orbit.

Geostationary Earth Orbit (GEO) -  When positioned in this orbit, a satellite appears to be fixed in space from the Earth because it is moving at the same speed as Earth is rotating (see Clarke orbit).

Geosynchronous - The position in space (at an altitude of 22,237 miles) where the speed of the satellite matches the speed of Earth's rotation.

GFCI or GFI - see Ground Fault Circuit Interrupter.

Gigabit - One billion bits.

Gigabyte - A measurement of bytes equal to 2 raised to the 30th power (i.e., 1,073,741,824 bytes).

Gigahertz (GHz) - A measure of frequency: one billion cycles per second.

Global Positioning System (GPS) - This is a system of 21 satellites, maintained by the US Government, that allows a user to figure out precisely where he or she is on Earth.

Google - The world's current dominating search engine. http://www.google.com

Googolbyte - This is 10 raised to the 100th power bytes.

GPS - see Global Positioning System.

Gravity - This is one of the four physical forces in the universe (the others being the electromagnetic force, and strong and weak nuclear forces); specifically it is the force of attraction that exists between all masses in the universe. It is proportional to the masses of the two bodies and inversely proportional to the square of the distance between them.

Gregorian Dual - This is a reflector antenna system that uses a parabolic main reflector and a concave ellipsoidal sub-reflector.

Ground - Connecting the Earth to electrical equipment with a conductor. This is done so current overloads (perhaps due to a lightning strike) can be safely diverted to the Earth.

Ground Fault Circuit Interrupter (GFCI or GFI) - This is a safety device, present in many household outlets, that will interrupt the current in an electrical circuit when the fault current goes over a certain value.

Ground Station - The satellite equipment located on the ground that controls the satellite and the information that is sent and received by the satellite.

G/T - A measure expressed in dB that is the ratio of the net gain (G) of the system and the noise temperature (T) of the system. Since you want to reduce noise temperature, a better system has a higher G/T.

Guard Band - This is a narrow piece of bandwidth that acts as a buffer between channel frequency bandwidths, with the intent of reducing interference. (See Guard Channel.)

Guard Channel - The channels that are transmitted together by satellites are kept apart by buffer zones called guard channels. A guard channel is several MHz wide and reduces the risk of channels interfering with each other. (See Guard Band.)