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Flashcards in Radar Theory Deck (21)
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1

What does PRP stand for and what is it?

Pulse Recurrence Period

The time taken to transmit a pulse and the quiet period waiting for the return. Basically the time from the start of one pulse to the next

2

What does PRF stand for and what is it?

Pulse repetition frequency

The amount of pulses sent every second

3

Formula to find PRP =

1 / PRF

4

Formula to find PRF =

1 / PRP

5

When using the PRP or PRF formula, what must the time be converted into?

Seconds (not microseconds etc)

6

The further away the target is, the smaller/bigger the PRP, and smaller/bigger the PRF

Why?

Bigger

Smaller

At long range there must be a long enough quiet/listening period to allow the returning beam to reach the aerial so the time between pulses will be greater, and therefore the amoount of pulses per second will be lower

7

Long range radar scanner rotation must be fairly slow because?

The returning pulses may miss the scanner if it is too fast

8

A shorter PRP would mean a higher/lower PRF?

Higher

9

Bearing accuracy is mainly controlled by?

Width of the beam

10

Minimum radar range in meters formula =

c x pulse length / 2

11

Radar beam width formula = 

70 x wavelength / antenna diameter

12

What affects the minimum range of a radar and why?

Pulse length because if it is sending the pulse for too long the returning wave could reach the aerial before it has finished transmitting and will not be recorded. Therefore, a short pulse length needs to be used for short range radar

13

Max radar range formula =

c / 2 x PRF

14

What size antenna diameter provides the narrowest beam width?

Larger diameter

15

What produces best range resolution?

Short pulses

16

Pulse power is quoted as the continuous power of a radar, which is ...

pulse power averaged over a complete transmission cycle

17

En-Route Surveillance radar operates at max ranges of ... to ... NM

200 - 300

18

En-Route Surveillance radar operates on ... MHz with a wavelength of ... and pulse length of ... microseconds

600

50cm

4

19

Terminal Surveillance Radar is medium range up to ... to ...NM

60 - 80

20

Terminal Surveillance Radar operates in top end of UHF at ... to ... MHz with a pulse length of ... microseconds

1000 - 1200

3.9

21

Max error of precision approach radar is +/- ... ft in azimuth and +/- ... ft in elevation

30

20