Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
Radar surface-angular measurements are referenced to true north and measured in what plane?
|
Horizontal plane.
|
|
The distance from a radar set to a target measured along the line of sight is identified by what
term? |
Range.
|
|
What is the speed of electromagnetic energy traveling through air?
|
Approximately the speed of light (162,000 nautical miles per second).
|
|
How much time is required for electromagnetic energy to travel 1 nautical mile and return to the
source? |
12.36 microseconds.
|
|
In addition to recovery time, what determines the minimum range of a radar set?
|
Pulse width.
|
|
Atmospheric interference with the travel of electromagnetic energy increases with what rf energy characteristic?
|
Frequency
|
|
How is prt related to prf?
|
1/PRT= PRF
|
|
What type of radar transmitter power is measured over a period of time?
|
Average power.
|
|
What term is used to describe the product of pulse width and pulse-repetition frequency?
|
Duty cycle.
|
|
What type of target bearing is referenced to your ship?
|
Relative bearing.
|
|
What type of radar detects range, bearing, and height?
|
Three-dimensional.
|
|
What characteristic(s) of radiated energy is (are) altered to achieve electronic scanning?
|
Frequency or phase.
|
|
What term is used to describe the ability of a radar system to distinguish between targets that are close together?
|
Target resolution.
|
|
The degree of bearing resolution for a given radar system depends on what two factors?
|
Beam width and range.
|
|
What happens to the speed of electromagnetic energy traveling through air as the altitude
increases? |
Speed increases.
|
|
What term is used to describe a situation in which Atmospheric temperature first increases with altitude and then begins to decrease?
|
Temperature inversion.
|
|
What radar subsystem supplies timing signals to coordinate the operation of the complete
system? |
Synchronizer.
|
|
When a transmitter uses a high-power oscillator to produce the output pulse, what switches the oscillator on and off?
|
High-voltage pulse from the modulator.
|
|
What radar component permits the use of a single antenna for both transmitting and receiving?
|
Duplexer.
|
|
What is the simplest type of scanning?
|
Single lobe.
|
|
How does the operator of a single-lobe scanning system determine when the target moves off the lobe axis?
|
The reflected signals decrease in strength.
|
|
What are the two basic methods of scanning?
|
Mechanical and electronic.
|
|
Rotation of an rf-feed source to produce a conical scan pattern is identified by what term?
|
Nutation.
|
|
The Doppler effect causes a change in what aspect of rf energy that strikes a moving object?
|
Frequency.
|
|
The Doppler variation is directly proportional to what radar contact characteristic?
|
Velocity
|
|
The Doppler method of object detection is best for what type objects?
|
Fast-moving targets.
|
|
The beat frequency in a swept-frequency transmitter provides what contact information?
|
Range
|
|
What factor determines the difference between the transmitted frequency and the received frequency in an fm transmitter?
|
Travel time.
|
|
What type of objects are most easily detected by an fm system?
|
Stationary
|
|
What transmission method does NOT depend on relative frequency or target motion?
|
Pulse modulation.
|
|
What transmission method uses a stable cw reference oscillator, which is locked in phase with the transmitter frequency?
|
Pulse-Doppler.
|
|
What type of radar provides continuous range, bearing, and elevation data on an object?
|
Track radar.
|
|
Radar altimeters use what type of transmission signal?
|
Frequency modulated (fm).
|
|
A surface-search radar normally scans how many degrees of azimuth?
|
360 degrees.
|
|
What limits the maximum range of a surface-search radar?
|
Radar horizon.
|
|
What is the shape of the beam of a surface-search radar?
|
Wide vertically, narrow horizontally.
|
|
Air-search radar is divided into what two basic categories?
|
2D and 3D.
|
|
What position data are supplied by 2D search radar?
|
Range and bearing.
|
|
Why do 2D air-search radars use relatively low carrier frequencies and low pulse-repetition rates?
|
Increased maximum range.
|
|
Why is the range capability of 3D radar usually less than the range of 2D radar?
|
Higher operating frequency.
|
|
Fire-control tracking radar most often radiates what type of beam?
|
A narrow circular beam.
|
|
Tracking radar searches a small volume of space during which phase of operation?
|
Acquisition.
|
|
What width is the pulse radiated by fire-control tracking radar?
|
Very narrow.
|
|
Which beam of missile-guidance radar is very wide?
|
Capture beam.
|