EQT 4 SSR Flashcards Preview

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Flashcards in EQT 4 SSR Deck (26):
1

What is SSR

A system of RADAR using ground interrogators and airborne transponders to determine the position of aircraft in range and azimuth.

2

What frequency does the interrogator transmit on?

1030mhz

3

What frequency does the interrogator receive on

1090mhz

4

Why do the frequencies for TX and RX have to be different

To stop self interrogation

5

What length wavelength is used for SSR

30cm

UHF/SHF

6

What is Mode A used for

Identification (squawk)

7

What is Mode C used for

Vertical position (height)

8

How does an a/c transponder know which type of interrogation

The different timings between pulses

9

What code do transponders use to respond

Binary

10

How long between mode A pulses

8.5 micro seconds

11

How long between mode C pulses

21 micro seconds

12

How many info pulses are in a Mode A reply?

12 info pulses

4 numbers for squawk (only 0-7 possible due binary)

13

How many possible squawks are there

4096

14

What are the 3 types of codes

Discrete

Non discrete

Special codes

15

What are the special codes

7500
7600
7700

16

What does ORCAM stand for

And who is in charge of it

Originating region code assignment method

Eurocontrol

17

How many participating areas is ORCAM divided into

5

18

What are the benefits of an ORCAM squawk

Reduces RTF and cockpit workload

Squawk can be retained take off until touch down

19

How many blocks of codes to ACCs have and what are they

2

Internal and international

20

Mode C reply

How many bits?

What does it give?

Give height read out

Uses 11 bits

3 number for height, 8&9 required so 11 bits to fit binary numbers in

21

What is the max uplink capacity

23 bits

11 Mode C

12 Mode A

22

What is Garbling

False codes display of A/C are so close together their responses to Mode A interrogation overlap

23

What do you use to overcome garbling

Degarbler

24

What is FRUIT

False response un-synchronised in time

Replies that have not been triggered by the interrogator

25

How do you remove fruit

With a defruiter

26

What is mono pulse SSR and why use it

Single pulse used. Average measurements made on several or all of the pulses received.

Improves accuracy

Fruiting and garbling minimised