Flashcards in NAVEDTRA 14190A NEETS Mod. 18, Ch. 1 Deck (43)
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1
Which term is used to refer to electronic equipment that detect the presence, direction, height, and distance of objects by using reflected electromagnetic energy?
Radar
2
What is used by radar sets to determine the direction and distance of the reflecting object?
Echo
3
The surface of the earth is represented by an imaginary flat plane, tangent (or parallel) to the earth’s surface at that location. What is this plane referred to as?
Horizontal plane
4
What is the line from the radar set directly to the object referred to as?
Line of Sight (LoS)
5
What is the angle called between the horizontal plane and the los?
Elevation angle
6
Approximately how many statute miles per second does electromagnetic energy travel through the air?
186,000
7
Approximately how many nautical miles are equal to 186,000 statute miles?
162,000
8
Approximately how many feet are there per nautical mile?
6,080
9
What is radar timing usually expressed in?
Microseconds
10
Approximately how many feet per microsecond does radiated energy from a radar set travel at?
984
11
The range in nautical miles to an object can be found by measuring the elapsed time during a round trip of a radar pulse and dividing this quantity by what number?
12.36
12
Which pulse property determines the maximum range that the pulse can travel to a target and still return a usable echo?
Peak power
13
What is the smallest signal called that is detectable by a receiver system that can be processed and presented on an indicator?
Usable echo
14
What is the frequency of the rf energy in the pulse radiated by a radar referred to as?
Carrier frequency
15
Radio frequency energy above what frequency is rapidly attenuated by the atmosphere?
3,000 megahertz
16
What is used to calculate both the peak power and average power of a radar system?
Duty cycle
17
Which radar target property is the angle between true north and a line pointed directly at the target?
True bearing
18
Which radar systems are designed to determine only the range and bearing of an object?
2D
19
Which type of search radar system detects altitude as well as range and bearing?
3D
20
Which radar property is defined as its ability to distinguish between targets that are very close together in either range or bearing?
Target resolution
21
Which two categories is resolution usually divided into?
Range and Bearing
22
What is the ability referred to as of a radar system to distinguish between two or more targets on the same bearing but at different ranges?
Range resolution
23
What is the ability of a radar system to separate objects at the same range but at different bearings?
Azimuth resolution
24
What is a measure of the ability of a radar system to determine the correct range, bearing, and, in some cases, height of an object?
Radar accuracy
25
What is the bending of electromagnetic waves caused by a change in the density of the medium through which the waves are passing?
Refraction
26
What ensures that all circuits connected with the radar system operate in a definite timed relationship?
Synchronizer
27
What is essentially an electronic switch that permits a radar system to use a single antenna to both transmit and receive?
Duplexer
28
What is the systematic movement of a radar beam in a definite pattern while searching for or tracking a target?
Scanning
29
Which type of scanning is unsuitable for use as a tracking radar?
Single-lobe
30
