An approach to the construction of a radar employing the 120-foot Haystack antenna at a wavelength of approximately 4 cm., a transmitter capable of producing 500 Kw of average power, and a maser preamplifier for the receiver is described. The system is expected to have a threshold (signal-to-noise in a 1 - cps filter) of 355 decibels. Extended integration can increase this factor by about 10 decibels. This radar performance ...