A certain circularly scanning radar with a fan beam has a rotation rate of 3 seconds per revolution. The azimuth beamwidth is 3 degrees and the radar uses a PRI of 600 microseconds. The radar pulse width is 2 microseconds and the radar searches a range window that extends from 15 Km to 100 Km. It is desired that the false alarm rate not be higher than two false alarms per revolu- tion. What is the required probability of false alarm? What is the minimum SNR so that minimum probability of false alarm can be maintained?