A document describes a method of calibrating phase differences among ground antennas in an array so that the maximumintensity direction of the far-field interference pattern of the array coincides with the direction for aiming the antennas to enable radio communication with a distant spacecraft. The method pertains to an array typically comprising between two and four 34- m (or similar size) antennas. The antennas are first calibrated pair-wise to maximize the uplink power received at a different spacecraft that is close enough for communication via a single ground antenna.