15. 'LASER' is used in communication at
A. microwave frequencies
B. millimetre wave length
C. light frequencies
D. all the above
16. A `radome' is a
A. protective cover for the antenna
B. radar housed in a dome
C. dome-shaped radar antenna
D. circular radar
17. The sensitivity of a radar receiver is ultimately set by
A. high S/N ratio
B. lower limit of signal input
C. overall noise temperature
D. low ? rator
18. A PPI displays
A. range versus angle
B. amplitude versus frequency
C. range and amplitude versus frequency
D. doppler frequency versus range
19. 'Second time around' echoes are caused by
A. second time reflection from target
B. echoes returring from targets beyond the cathode ray tube range
C. echoes that arrive after transmission of the next pulse
D. None of the above
20. A simple CW radar does not give range information because
A. it uses the principle of Doppler shift
B. continuous echo cannot be associated with any specific part of the transmitted wave
C. CW waves do not reflect from a target
D. None of the above
21. The best system for tracking a target after it has been acquired is
A. helical
B. nodding
C. conical
D. monopulse
Page 3 of 39