Forming a beam from a subscriber module of a fixed wireless access communication system

A method of forming a beam from a subscriber module of a fixed wireless access communication system, the subscriber module having an offset Gregorian antenna system comprising a primary reflector dish, a secondary reflector, an array of antenna elements and a beamforming network, the beamforming network being configured to form a beam using an antenna weight vector selected from a pre-determined plurality of antenna weight vectors, wherein the array of antenna elements is arranged to feed the secondary reflector to form the beam from the primary reflector dish, the method comprising:

• providing the pre-determined plurality of antenna weight vectors configured to form a plurality of beams, the orientations of the plurality of beams being arranged in a grid comprising a plurality of rows, each of the pre-determined plurality of antenna weight vectors being configured to form a respective beam from the primary reflector dish of the Gregorian antenna arrangement by forming a respective feed beam from the array of antenna elements,
• wherein the array of antenna elements and the secondary reflector are offset in a vertical axis with respect to a centre of the primary reflector dish, and the relationship between the azimuth and elevation direction of each feed beam and the azimuth and elevation direction of the respective beam from the primary reflector dish is a non-linear function of azimuth and elevation.