The parabolic shape focuses the weak microwave signal hitting the surface of the dish into a single focal point in front of the dish where the feedhorn is usually located. Programmer Originator of television programs transmitted via satellite. Selectivity Ability of receiver to reject transmissions from frequencies other than the specific one to which it is tuned. Difference of 45 dB is required for clear reception. True North Geographic north, determined by the earth's axis.
True north is one of the measurements used to align satellite antennas with the satellites.
Magnetic north is determined by the earth's magnetic poles. An industry term meaning Television Receive Only. Describes antennas designed to receive satellite signals.