Minitrack, short for "Minimum Tracking," was designed and built to track the Vanguard satellite. Its antenna provided a fan-shaped receiving pattern through which a satellite passed, and signals received from the satellite were converted into measurements that plotted the satellite's orbit. Personnel from the New Mexico State University Physical Science Laboratory designed, calibrated, and installed antennas like this one at fourteen Minitrack sites around the world. The Minitrack network began operation in October 1957. The system installation was completed three days before the Soviet Union launched Sputnik, and although it had been designed to respond to 108 MHz signals while Sputnik transmitted at 20 and 40 MHz, engineers modified the network for the different frequency and were tracking Sputnik within 24 hours.