单项选择题
A.the shore is bluff and rocky B.of offshore exposed rocks C.submerged reefs cause prominent breakers D.the lookout tower is marked with radar reflectors
The radio waves used for radar are very short,only()lon...
单项选择题The radio waves used for radar are very short,only()long.
A.a few centimeters B.a few fathoms C.a few meters D.a few feet
The radar control used to reduce sea return at close ra...
单项选择题The radar control used to reduce sea return at close ranges is the().
A.gain control B.sensitivity time control C.fast time constant D.pulse length control
The radar control that shortens all echoes on the displ...
单项选择题The radar control that shortens all echoes on the display and reduces clutter caused by rain or snow is the().
A.sensitivity time control (sea clutter control) B.receiver gain control C.brilliance control D.fast time constant (differentiator)