The Low Gain Antenna (LGA) is an antenna with a broad radiowave beam width. This very wide beam allows for a more reliable signal that is best used in mountainous regions, where the signal will propagate reasonably well regardlesss of terrain. The mountains become the equivalent of rocks in a stream, surrounded by the flowing waves. Low gain antennas are often used in spacecraft as a backup to the High Gain Antenna, which transmits a much narrower beam and is therefore susceptible to loss of signal.
