The large synthesis radio telescopes of the National Radio Astronomy Observatory

It is noted that large radio telescope arrays such as the Very Large Array and Very Long Baseline Array at the National Radio Astronomy Observatory challenge the state of the art of microwave technology in many areas. Examples include the design of optimized sparse arrays and the design and the economic construction of high-performance, frequency-flexible antennas, reliable low-noise receivers, and highly phase stable local oscillator systems. Some of the microwave technology used in these instruments is described.<>