An unwanted signal which interferes with reception of the desired information. Feed A feed which is offset from the center of a reflector for use in satellite receiving systems. Most PWPL antenna have offset feeds. The attenuation that a signal undergoes in traveling over a path between two points. Parabola The geometric shape that has the property of reflecting all signals parallel to its axis to one point, the focal point.
Satellite antennas are parabolic.
Polarization A characteristic of the electromagnetic wave. PWPL signals use horizontal and vertical. A parabolic dish having the feed assembly at the focal point directly in the front of the antenna. Also known as a center-fed antenna. The opposite of off-set fed antennas.