Basic Radar Concepts
Radar Surface angular measurement are referenced to true north and measured in what plane?
Horizontal plane.
True Bearing
The bending of electromagnetic caused by a change in the density is known as what?
refraction
What component supplies the signal that time the transmitted pulses, the indicator, and associated circuits.
Sychronizer
What is a systematic movement of a radar beam in a definite pattern while searching for or tracking a target.
scanning
The distance from a radar set to target measured along the line of sight (LOS) is identified by what term?
Range
What is the difference between a 2d and 3d radar?
2d measures both range and bearing while 3d includes altitude with range and bearing.
Bending of the radars waves passing through abnormal conditions is known as what?
ducting
Generates electromagnetic energy in the form of short powerful pulses.
Transmitter
The Doppler effects causes a change in what aspect of RF energy that strikes a moving object?
Frequency
What is the speed of electromagnetic energy traveling through air.
The speed of light (162,000 NM per second.)
What type of target bearing is referenced to your ship?
relative bearing
The beam is scanned either in ______ or ________?
electronically or mechanically
What does the duplexer do?
allows the same antenna to transmit and receive
A surface search radar normally scans how many degrees of azimuth?
360
In addition to recovery time what determines the range of a radar set?
Pulse width
How do you measure true north?
True north is measured in the horizontal plane and in a clockwise direction from true north.
What term is used to describe a situation in which atmospheric temperature first increase with the altitude and then begins to decrease.
Temperature inversion
What does the receiver do?
Receives echo signals and amplifies them, detects a pulse envelop and amplifies them, then routes them to indicator.
Why 2d air search radars use relatively low carrier frequency and low pulse reptation rates (prr)?
increase maximum range
How much time is required for electromagnetic energy to travel one NM and return to source?
12.36 microseconds
How does the antenna radiate energy? (in one direction)
Lobe or in a beam (they can be moved simply by moving the antenna)
Atmosphere close to surface over large bodies of water may contain more than a normal amount of moisture and thus content may decrease more rapidly at heights just above sea is known as what?
Moisture lapse
What does the antenna do?
Routes the pulse from the transmitter, radiates it in a directional beam, picks up returning echo's and passes it to receiver with minimum loss.
What is the shape of the beam of a surface search radar?
wide vertically
narrow horizontally