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NC RADAR OPERATOR FINAL EXAM 2025
QUESTIONS AND ANSWERS GRADED A+
To examine how reflected radio signals are changed by relative motion requires an understanding of ___ those signals.
wave nature
The wave length is literally the physical distance, or length from the?
Beginning of the peak to the end of the valley
The number of waves transmitted in one second of time equals the?
Frequency
All radio waves have three distinguishable characteristics.
Signal speed, wave length, frequency
Every RADAR signal travels at the same speed, namely the?
Speed of light
Both the transmitted and received RADAR signals ___ travel at that constant speed.
always
Most RADAR signals in North Carolina today have wave lengths of about ___ (between .35 and .33 inches).
4/5 centimeters
Police RADAR signals have frequencies of more than ___ waves per second?
10 billion
Which of the following have exactly the same meaning?
One hertz = one cycle = one wave per second
X-band radar signal is ___ gigahertz?
30 billion
The radar signal's speed stays the same, but its __ and __ both change.
wave length; frequency
Who was the Austrian physicist credited with having discovered that relative motion causes a signal's frequency to change?
Christian Johann Doppler
Doppler discovered that relative motion causes a signal's frequency to change by?
Studying sound waves
What state agency is charged with the responsibility of developing and implementing mandatory criminal justice training courses, including the speed measuring instrument operator training courses?
Criminal Justice Education and Training Standards Commission
Minimum hours required for RADAR operator course? Shall not exceed?
30 hours; shall not exceed 4 consecutive weeks
Minimum ratio of instructors per students?
1 instructor per 6 students
The trainee must demonstrate ___ percent competence in the setup, test for accuracy and operation of the RADAR.
100%
Maximum sign off time?
2 hours
Required amount of supervised field practice time?
12 hours within 90 days
RADAR operator re-certification training shall consist of a minimum of ___ and shall not exceed ___.
6 hours; 1 week
RADAR is only a?
Tool
We are primarily concerned with?
Speed enforcement
According to NHTSA, the percentage of fatal crashes that occur in a speed zone of ___ or less is about 15%, while 65% occur in a ___ speed zone.
40 mph; 55 mph
What do we expect to accomplish?
Improve effectiveness of speed enforcement through the proper and efficient use of speed measuring instruments.
The basic goal of all police work is?
Protect the lives and property of the public
One of the best known challenges to RADAR occurred where and when? Which resulted in the rejection of RADAR evidence in 80 speed cases.
Dade County, Florida in 1979
IACP
International Association of Chiefs of Police
In order for a RADAR speed-measuring device to be approved for use in North Carolina, the instrument must be on the IACP ___?
Consumer Products List
What has been the target in almost all successful challenges to RADAR?
Human error
How good is RADAR?
Only as good as you, the operator
4 times, 4 times, and 16 times
The braking distance at 40 mph is not twice the distance required at 20 mph, but?
4 times
According to Joseph Nathan's Famous Firsts, the very first traffic law in America was passed on June 12, 1652 in?
New Amsterdam (now New York)
Hartford, Connecticut speed regulation
Enacted in 1901, limited automobile speeds to 12 mph in the country and 8 mph in within the city limits.
Basic Speed Law
Law stating that you may not drive faster than is safe and prudent for existing conditions, regardless of posted speed limits.
Prima Facie
At first sight / glance
Absolute Speed Limits
Simply prohibit driving faster than a specified numeric speed.
What are the three North Carolina speed laws?
Absolute, posted limit, and basic speed law.
What are the two aspects of driver identification?
Officer must identify the driver at the time of the violation, and in court.
With the oil embargo of 1973, congress imposed a nationwide ___ MPH max speed in 1974?
55
55 mph was chosen because it is the?
Median energy efficiency speed
NHTSA and TSF in NC found that speed attributed to ___ percent of all highway deaths.
38.7% - 39%
A very substantial number approximately ___ percent of fatal crashes in North Carolina occur in local jurisdiction.
approximately 25%
RADAR is a simple concept; in that a radio beam is transmitted out at a certain frequency, strikes an object with ___, where the frequency is changed (increased or decreased) and reflected back to the antenna.
relative motion
The word "RADAR" is an acronym, an abbreviation of the phrase RAdio Detection And ___?
Ranging
The police radar provides us with the speed reading on a detected target but not the ___ to the target?
range
The range information provided may be expressed in?
Yards or feet
The radar's transmitted beam will travel ___ unless it is absorbed, reflected, refracted.
Infinitely
___ is generated by a transmitter, the antenna forms the energy into a beam and the energy is transmitted into space.
Radio frequency energy
The operation of the Radar's timing circuits are made possible by the fact that radio energy always travels at approximately?
186,000 miles per second
Both the transmitted and received Radar signals always travel at a ___ speed.
constant
The ___ of the relative motion determines exactly how much higher or lower the reflected signal will be.
speed
The key thing about the Doppler Principle is that the frequency change only happens when there is __ __ between the radar and the solid object.
relative motion
The angular effect is also known as?
Cosine effect
Relative motion will occur if?
- The RADAR stands still and the object moves:
- The object stands still and the RADAR moves; or
- If they are both moving, as long as they move at different speeds, or in different directions so that the distance between them changes.
A ___ radar will measure the true speed of an object only when that object is moving directly toward or directly away from the radar.
stationary
In order to minimize that stationary radar angular effect, we always want to keep the angle as ___ as possible.
small
When selecting a site to operate stationary radar, it should be as ___ as possible.
safe and close to the road
The closer we set up to the traveled portion of the road, the better control we have over the ___ ___.
angular effect
In NC, RADAR instruments operated in the stationary mode must be set up so the angle between the RADAR and the target vehicle is no greater than?
20 degrees
How we ___ , or ___ , the radar device will have an impact on the magnitude of the angular effect.
aim; point
If the vehicles tend to be widely separated, a ___ setting should be used.
longer range
In stationary radar the angular effect is always in whose favor?
Suspect
Depending on ___ of the object, its reflected signal may not be "seen" by the RADAR unit.
size, shape, speed, composition and exact location
If we are operating radar at locations where vehicles tend to travel clustered to one another, a relatively ___ setting should be used.
shorter range
If the vehicles tend to be widely separated, a ___ setting should be used.
longer range
The transmitter's antenna focuses most of the energy into a?
Cone-shaped beam
The narrowest-beam RADAR currently available is about?
9 degrees
A radar beam whose angle is 11 degrees will be more than ___ ft wide at a point 200 feet down the road.
38
A radar beam will be more than 57 ft wide at a point ___ ft away.
300
When we adjust RADAR's "range" we are actually adjusting the ___ of the radar receiver.
sensitivity
It is important to understand that a RADAR unit's range setting is?
