Abstract: An MLS system having redundant subsystems. Dual signal sources feed dual power dividers. A first switch array selects the power divider to be used and provides the selected signals to an array of phase shifters. A second switch array provides the phase shifted signal, which may be amplified, to either a primary array having elements for radiating a scanning beam or a recombining network having outputs connected to auxiliary antennas. A third switch array provides control signals to the array of phase shifters from either a main beam steering unit or a standby beam steering unit. Alternatively, the dual signal sources feed a single power divider through a circulator. Duplicate auxiliary antennas may be used with antenna switches located before the power dividers or circulator for selectively providing the signals to the auxiliary antennas instead of the primary array.