DESIGN AND IMPLEMENTATION OF A LOW-NOISE PRIME-FOCUS S X RECEIVER SYSTEM FOR RADIO ASTRONOMY/

This paper discusses the design, construction, and measured performanc e of dual-band, dual-polarization, prime focus receiver systems used o n three antennas at the NRAO facility in Green Bank, WV. The receivers operate at S- and X-bands near 23 and 8.4 GHz. Described is the devel opment of a new dualband feed horn, a cryogenics package with waveguid e input ports using HEMT low-noise amplifiers, and a receiver system u sing optical fiber microwave links to transmit frequency reference and IF signals. Measured performance of major components and the overall installed system is given.