NRTC 14190A RADAR FUNDAMENTALS
in a monopulse scanning system, which of the following feedhorn signal combinations makes up the bearing signal
(A + C) - (B + D)
for a radar set with a pulse width of 25 microseconds and a prf of 600 pulses per second, what is the duty cycle
0.015
a radar set with a prf of 1000 pps and an antenna rotation rate of 15 rpm produces what maximum number of pulses per degree
11.1
what is the maximum radar horizon distance for a radar set with an antenna 100 ft above the surface of the earth
12.5 miles
for an object that is detected 15 miles from a radar set, what is the approximate time required for the rf energy to travel to and return from the object
185 microseconds
which of the following formulas can be used to compute the duty cycle of a radar set
2
what is the approximate range resolution (in yards) of a radar set with a pulse width of 15 microseconds and a peak power of 2 kilowatts
2460
what is the pulse-repetition time (in seconds) for this radar set
2500
complete control of a beam-rider missile requires what minimum number of radar beams
3
what is the peak power (in kilowatts) for this radar set
500
the minimum range of a radar depends on the length of time of the transmitter pulse (pulse width) and recovery time. during this period, the radar can NOT receive energy. a radar set with a pulse width of 5 microsecond and a recovery time of 0.2 microseconds has a minimum range of approximately
852 yards
in a monopulse scanning system, which of the following combinations make up the range signal
A + B + C + D
which of the following JETDS classifications identifies a shipboard fire control radar set
AN/SPG-55
at any given distance from the antenna, the radar beam axis of a conical-scan antenna follows what pattern
a circle around the scan axis
in a single stationary-lobe scanning system, complete azimuth coverage is achieved by which of the following methods
a continuously rotating antenna
to make amplification of received rf energy easier, the returning rf signal is converted to a lower, intermediate frequency. What component of the radar system performs this function
a superheterodyne receiver
when a fire-control radar antenna approaches the general direction of a target, the radar enters which of the following modes of operation
acquisition
long-range aircraft detection is provided by which of the following types of radar
air search
in a pulse radar system, which of the following components should you expect to find
all of the above
refractions and speed changes are known to occur in electromagnetic wavefronts. these phenomena are caused by which of the following conditions
all of the above
the type and method of scanning used by a radar system depends upon which of the following radar system design considerations
all of the above
which of the following are typical characteristics of surface-search radars
all of the above
which of the following characteristics is/are typical of a fire-control radar
all of the above
which of the following terms describes radar returns that exceed the prt of the radar
ambiguous
what type of transmitter power is measured over a period of time
average
the width of a radar beam and range to a detected object are the determining factors in which of the following radar system characteristics
bearing resolution
in the cw radar transmission method, the Doppler effect provides which of the following target information
both 1 and 2 above
range information can be obtained in a doppler radar by which of the following methods
both 1 and 2 above
for most military applications, which of the following radar systems is/are used
both track and search radars are used
frequency-modulated radar transmit a wave that continuously changes in frequency about a center frequency. using frequency modulation, the range to a target is determined by using which of the following methods
by comparing the frequency of the transmitted signal with the returned frequency from the target
in a conical-scan antenna, nutation of the radar beam is usually accomplished by which of the following methods
by moving the feed point
which of the following characteristics of a radar system determines the degree to which the radiated energy is affected by atmospheric conditions
carrier frequency
the relative bearing of a radar echo is measured with respect to which of the following reference points
centerline of your own ship
the frequency of the returned signal increases when a target is approaching an decreases when a target is moving away in which of the following types of radar systems
doppler
temperature inversions and/or moisture lapses in the atmosphere may extend or reduce the range of a radar by creating
ducts
which of the following radar components allows the use of one antenna for both transmitting and receiving radar energy
duplexer
which of the following methods can be used to achieve radar-beam scanning
each of the above
electromagnetic energy travels through air at approximately what speed
each of the above is correct
radar uses what form of energy to detect ships, place, and land masses
electromagnetic energy
which of the following types or radar provides accurate range, bearing, and altitude of aircraft
height-finding
the range capability of a 3D radar is limited by which of the following characteristics
high operating frequency
the elevation angle to the target is the angle between which of the following references
horizontal plane and line of sight
which of the following are characteristics of a typical air-search radar
low frequency
what component of the transmitter supplies the trigger pulse, which acts as a switch to turn the klystron on and off
modulator
to detect nearby objects, the output pulse of a radar transmitter should possess which of the following characteristic shapes
narrow and square
fire control radars must be directed to the general location of a desired target. This is because of which of the following characteristics
narrow beam pattern
altitude or height finding radar systems require a beam with which of the following characteristics
narrow in the vertical plane
continuous-wave radar that uses the doppler effect is best used in detecting which of the following types of targets
past-moving
pulse-repetition is described as the
period time from the beginning of one transmitter pulse to the beginning of the next
which of the following statements describes the advantage of using pulse modulation (pm) rather than continuous wave in a radar system
pm does not depend on target motion; cw does
target resolution is the ability of a radar to distinguish between targets that are ar nearly the same range and/or bearing. range resolution is dependent on which of the following factors
pulse width and target size
the sweep frequency of a radar indicator is determined by what parameter of the radar system
pulse-repetition frequency
monopulse receivers use what signal as a phase reference
range
of the following radar characteristics, which has no effect on maximum range capacity
recovery time
which of the following factors has/have the greatest effect on the accuracy of a pulse radar
resolution
what radar measurement of an object is references to true noth
surface angle
detection of surface and low-altitude air targets is the primary purpose of which of the following types of radar
surface search
in a pulse radar system, what component controls timing throughout the system
synchronizer
in a mononpluse scanning radar, the relative position of a target with respect to the radar-beam axis is determined by comparing which of the following signal componenets
the amplitudes of the returning rf energy in each horn
which of the following radars would most likely be used to direct CAP aircraft during an intercept
three-coordinate radar
in doppler radar, some definite relationship must exist between the transmitted frequency and the reference frequency. For what purpose is this relationship used
to detect the doppler shift of the received signal
