The Agilent 8511A, a 45 MHz to 26.5 GHz frequency converter, when combined with the Agilent 8510C Network Analyzer results in a general purpose four-channel magnitude/phase receiver. Add your own power splitters for transmission measurements, and bridges or directional couplers for reflection measurements. Since one input is used for system phase-lock, the other three inputs are available for measurements of multiport devices, subsystems, and antennas. All four inputs on the Agilent 8511A have precision 3.5 mm connectors.