Radar

Question 1

What does radar stand for?

Answer 1

Radio detection and ranging

Question 2

How does the radar work?

Answer 2

It uses echo principle

Question 3

Pulse modulation

Answer 3

Determines the distance to a target by measuring the time required for an extremely short burst of radio frequency (r-f) to travel to the target and return. Direction antennas to determine the bearing.

Question 4

X-band radar

Answer 4

3cm @ 9300-9500 mhz

Question 5

S-band radar

Answer 5

10cm @ 2500-3100 mhz

Question 6

Radio frequency travels at what speed?

Answer 6

Speed of light. 162,000nm per second

Question 7

Speed of pulse radio frequency is so fast it can travel how fast in one second?

Answer 7

It can circumnavigate the globe 7 times in one second.

Question 8

Micro send=

Answer 8

1 millionth of a second(1,000,000 microseconds in a second)

Question 9

Cycle=

Answer 9

A complete oscillation or complete wave passing zero in one direction and zero again in the same direction.

Question 10

Frequency

Answer 10

Number of cycles completed per second

Question 11

One hertz =

Answer 11

1 cycle per second

Question 12

Kilohertz

Answer 12

1,000 cycles per second

Question 13

Wavelength

Answer 13

The distance along the direction of propogationbetween successive crests

Question 14

Watts

Answer 14

Inversely proportional to square distance. Power at 3 miles is 1/9th power at 1 mile.

Question 15

Voltage

Answer 15

Voltage at 2 miles is only 1/2 the voltage at 1 nautical mile.

Question 16

Horizontal beam width

Answer 16

Narrow 0.65 degrees to 2 degrees

Question 17

Vertical beam width

Answer 17

Broad 15-30 degrees

Question 18

Maxima

Answer 18

When direct and indirect waves are exactly in phase

Question 19

Minima

Answer 19

When direct and indirect waves are in opposition.

Question 20

Defraction

Answer 20

Bending of a wave

Question 21

Wavelength formula for 3cm radar•

Answer 21

D=1.22 square/h
D= distance to radar horizon in nautical miles
H=height of radar

Question 22

Attenuation

Answer 22

The reduction of intensity of the wave along its path. Greater at high frequencies and shorter at wavelengths. S-band (10cm) will suffer from less attenuation than x-band(3cm)

Question 23

What will suffer more from attenuation?

Answer 23

X-band(3cm)

Question 24

Rain squalls have more affect on which radar?

Answer 24

X-band(3cm)

Question 25

What radar is better in the rain?

Answer 25

S-band (10cm)

Question 26

Clouds/water droplets are picked up better on which radar?

Answer 26

S-band(10cm)

Question 27

Pulse repetition frequency

Answer 27

The majority of radars operate on 400-4000 pulses per second

Question 28

Lowering the gain setting

Answer 28

The maximum detection range is reduced but the narrower effective bean width provides better range detection

Question 29

What radar is better in the rain?

Answer 29

S-band(10cm)

Question 30

North up on the radar is

Answer 30

Stabalized display

Question 31

Stabalized display on the radar is

Answer 31

North up on the radar

Question 32

Heads up on the radar is

Answer 32

Unstabilized display

Question 33

Unstabilized display is

Answer 33

Heads up display

Question 34

Rain clutter

Answer 34

Variable fast time constant (shortens echos on display to produce less clutter)

Question 35

How do you shorten echos on display to reduce clutter?

Answer 35

Increase the rain dial

Question 36

Lagoons and inland lakes appear as what on the display?

Answer 36

Blank areas on ppi

Question 37

Coral stops and long chain islands appear as what on the display?

Answer 37

Long lines of echos when radar beam is perpendicular to them

Question 38

Racon =

Answer 38

Bearing and range info

Question 39

What type of land mass gives good echos

Answer 39

Wooden

Question 40

What type of land masses give off bad echos

Answer 40

Barren

Question 41

Raymark signal

Answer 41

Bearing info only

Question 42

Frequency agile racons are widespread and can be picked up by both s/x band radars but what radar is better for this?

Answer 42

X-band (3cm)

Question 43

Parallel indexing

Answer 43

Distance off an object when a beam, can be used to track drift

Question 44

What radar picks up SART signals

Answer 44

X-band (3cm)