English: Tooway dual-band direct broadcast satellite antenna drawing. This type is called an offset Gregorian design. The radio waves from the satellite reflect off the large dish (right), which is an asymmetrical segment of a paraboloid, and focuses them on the smaller concave elliptical reflector (left). This secondary reflector focuses them on the feed horn on the arm, where they are received, converted to an electrical signal, and processed in the LNB behind the horn. The purpose of this offset design is to move the concave secondary reflector out of the path of the beam.