Radar
How fast does electromagnetic energy travel
186,000 mps or 162,000 Nps or 984 ft per microsecond
Air search radar is divided into what two basic categories
2D and 3D
A surface search radar normally scans how many degrees of azimuth
360 degrees
How many king does it take for energy to travel one mile
6.18 micro seconds. Two way travel makes it 12.36 microseconds
Fire control radar most often radiates what type of beam
A narrow circular beam
Tracking radar searches a small volume of space during with phase of operation
Acquisition
What type of radar transmitter power is measured over a period of time
Average power
The degree of bearing resolution for a given radar system depends on what two factors
Beam width and range
Witch beam of middle guidance radar is very wide
Capture beam
What radar components permits the use of a single antenna for both transmitting and receiving
Duplexer
What term is used to describe the product of pulse width and pulse repetition frequency
Duty cycle
The Doppler method of object detection is best for what type of objects
Fast moving targets
The Doppler effect causes a change in what aspect of rf energy that strikes a moving object
Frequency
Radar altimeters use what type of transmission signal
Frequency modulation
What characteristic of radiated energy is altered to achieve electronic scanning
Frequency or phase
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
Why is the range capability of a 3D radar usually less then the 2D
Higher frequency
Radar surface angular measurements are referenced to true north and measured in what plane
Horizontal plane
Why do 2D air search radars use relatively low carrier frequencies and low pulse repetition rates
Increased max range
Long range coverage is better at what frequencies
Low frequencies because it is less affected by atmosphere
What are the two basic methods of scanning
Mechanical and electronic
Rotation of an rf fed source to produce a conical scan pattern is identified by what term
Nutation
What transmission method uses a stable cw reference oscillator, which is locked in phase with the transmitter frequency
Pulse doppler
What transmission method does not depend on relative frequency or target motion
Pulse modulation
What determines the minimum range
Pulse width
What limits the max range of a surface search radar
Radar horizon
What does radar stand for
Radio detection and ranging
The beat frequency in a swept frequency transmitter provides what contact information
Range
The distance from a radar set to a target measured along the line of sight is called what
Range
What position data are supplied by 2D search radar
Range and bearing
What type of target bearing is referenced to ur ship
Relative bearing
What is the simplest type of scanning
Single lobe
What happens to the speed of electromagnetic energy traveling through air as the altitude increases
Speed increases
What type of objects are most easily detected by an fm system
Stationary
What radar subsystem supplies timing signals to coordinate the operation of the complete system
Synchronizer
What term is used to describe the ability of a radar system to distinguish between targets that are close together
Target resolution
What term is used to describe a situation in which atmospheric tempature first increases with altitude then begins to decrease
Temperature inversion
How does the operator of a single love scanning system determine when the target moves off the lobe axis
The reflected signal decrease in strength
What type of radar detects range, bearing, and height
Three demensional
What type of radar provides continuous range bearing and elevation data on an object
Track radar
What factor determines the difference between the transmitted frequency and the recieved frequency in an fm transmitter
Travel time
The Doppler variation is directly proportional to what radar contact characteristic
Velocity
What width is the pulse radiated by fire control tracking radar
Very narrow
What is the shape of the beam of a surface search radar
Wide vertically narrow horizontally