Chapter 8 Basic Radar Theory

Question 1

What does primary radar detect an object based on?

Answer 1

Size and materials

Question 2

What does a radar transmitter emit?

Answer 2

Radio waves as a series of pulses in a directional beam

Question 3

What detects the reflected radio waves?

Answer 3

The receiver in a radar head

Question 4

What frequency is used for primary radar?

Answer 4

1-10 GHz (3-30cm) (UHF-SHF)

Question 5

What is beam width a function of?

Answer 5

Wavelength and dish diameter

Question 6

What is the pulse recurrence period?

Answer 6

The pulses are transmitted at a set time interval

Question 7

How is radar time measured?

Answer 7

In microseconds

Question 8

What is the pulse repetition frequency (PRF) or pulse recurrence rate (PRR)?

Answer 8

How many pulses per second

Question 9

What is the relationship between range and PRF?

Answer 9

Inversely proportional

Question 10

What is the formula for max unambiguous range?

Answer 10

Ruanmb = c / (2*PRF)

C = speed of light

Question 11

What is the formula max theoretical range?

Answer 11

Rmax = 1.23 * (sqrt Tx + sqrt Rx)

Question 12

What is the formula for minimum range?

Answer 12

Pulse width * 12.36 microseconds/nm

Question 13

What degrade radio waves?

Answer 13

Water vapour, temperature changes and pressure changes

Question 14

What is needed for effective reflection?

Answer 14

Wavelength less than target size

Question 15

What is the purpose of a moving target indicator?

Answer 15

To suppress all stationary echoes

Question 16

What does the MTI use?

Answer 16

Jittered PRF and Doppler shift