The word beam describes a signal that is transmitted over a narrow path. Satellites use a beam to transmit information from the satellite orbiting the Earth to the Antenna that catches the information. The antenna catches the beam as a data stream, and routes this through the satellite cables into your TV. The satellite beams forms a footprint over certain areas, showing the coverage and signal strength over various regions. The stronger the beam to more area it can cover and the better the signal reception.