Abstract :
The principles of operation of the maser are reviewed with emphasis on its ability to give low-noise amplification. The properties of the comb structure travelling wave maser are discussed and related to the microwave ¿space window¿, with special reference to an S-band amplifier which has been constructed. The performance of a receiver, incorporating a maser or a parametric amplifier, is analysed as a function of aerial noise temperature. The basic elements of a maser installation are described with particular regard to the problems of attaching it to an ultrasensitive receiver incorporating a fully steerable, highly directive low-noise aerial. Some consideration of possible cost is included.
