Radar | Secondary Surveillance Radar

Question 1

This improves on primary radar by using __-pulse secondary equipment to provide more information

Answer 1

double

Question 2

An interrogation ground station send a rotating beam of ___ modulated signals in all directions in a form that is recognised as a request for information

Answer 2

pulse

Question 3

A transponder is carried that receives interrogation pulses at ____ _Hz, superimposes information onto it, and sends it back on another paired frequency of ___ _Hz

Answer 3

1030 Mhz, 1090 MHz

Question 4

The interrogation and response pulses are ___ _Hz apart

Answer 4

60 Mhz

Question 5

Primary radar is ___ accurate in terms of bearing and distance

Answer 5

more

Question 6

Enhanced surveillance extracts additional information from the aircraft, known as ___

Answer 6

Downlink Additional Parameters - DAP

Question 7

Mode 3/A asks ____

Answer 7

who are you?

Question 8

Mode C asks ___

Answer 8

how high are you?

Question 9

Interrogations are sent as a pair of pulses and a ___ pulse

Answer 9

control

Question 10

The decoding time between the ___ pulses determines the operating mode of the transponder

Answer 10

interrogation

Question 11

A spacing for transmission and reception is called a ___

Answer 11

mode

Question 12

For modes 3/A, and C, a pair of pulses called __ and __ are sent to the aircraft

Answer 12

P1 P3

Question 13

Mode A has a ___ interval between pulses, whilst mode C has a ___ interval between them

Answer 13

shorter, longer

Question 14

An omnidirectional antenna sends out P2, which is ___ than the others, but stronger than any sidelobes.

Answer 14

weaker

Question 15

If the transponder can receive ___ ___ ___, it knows it’s receiving the main lobe, but it it sees __ then it knows it’s receiving a side lobe, with responses being avoided.

Answer 15

P1 and P3, P2

Question 16

Mode S uses a short __ pulse

Answer 16

P4

Question 17

A long P4 pulse means that the interrogator is transmitting a ___ ___ ___.

Answer 17

Mode A/C/S all call

Question 18

A special position ident pulse is sent by using the ___ switch

Answer 18

IDENT

Question 19

When answering an interrogation, Mode A transponders will transmit up to __ pulses, _ microseconds apart (__ for Mode B), with the first and last being frame pulses (__ and __) which enclose the whole signal so it doesn’t get muddled with others. The remaining __ can be there or not, in up to ___ combinations.

Answer 19

14 8 17 F1 F2 12 4096

Question 20

The IDENT pulse is transmitted for up to __ seconds

Answer 20

20

Question 21

Each number selection knob controls _ pulses; _ _ _ _

Answer 21

3, A, B, C, D

Question 22

Selecting 2300 would produce the codes ___

Answer 22

010
110
000
000

Question 23

0 means ___ signal, selecting 2, generating a pulse 010, means that only pulse _ of the pulse group is transmitted.

Answer 23

no, 2

Question 24

Mode C is just Mode _ plus altitude reporting

Answer 24

A

Question 25

Mode C sends flight level information from the aircraft in ___ft increments

Answer 25

100

Question 26

ATC's presentation gives information regarding your flight level that's accurate to within __ft, with the tolerance being __ft

Answer 26

50 300

Question 27

Mode C pulses are __ microseconds apart

Answer 27

21

Question 28

The S in Mode S stands for ___

Answer 28

selective

Question 29

Mode S pulses are __ microseconds apart

Answer 29

25

Question 30

Mode S gives each aircraft a unique code, allowing it to only respond to requests directed to them, as opposed to ___ requests.

Answer 30

all

Question 31

Mode S provides altitude reporting in __ft intervals

Answer 31

25

Question 32

With Mode S, the initial two pulses are followed by a ___ pulse containing a string of up to ___ bits.

Answer 32

long 112

Question 33

The first __ bits of the 112 bit string are a unique address to the aircraft

Answer 33

24

Question 34

Mode A/C/S all calls consists of 3 pulses __, __, __

Answer 34

P1 P3 long P4

Question 35

A control pulse __ is transmitted following __ to suppress responses from aircraft in the side lobes of interrogation antenna

Answer 35

P2, P1

Question 36

A Mode A/C only all call consists of 3 pulses __, __, __

Answer 36

P1 P3 short P4

Question 37

A Mode S transponder regularly delivers a squitter, which is a short transmission of basic data without a ___ ___, only to advertise the position

Answer 37

receiving request

Question 38

Mode S can provide a 2 way data link on ___ and ___ _Hz, used by TCAS

Answer 38

1030 1090 MHz

Question 39

Mode S equipped aircraft over ___kg or with max TAS over ___kts must use transponder antenna diversity

Answer 39

5700 250

Question 40

The two main functions of a Mode S transponder are __

Answer 40

- G/A and A/G data link | - Improved ATC aircraft surveillance capability

Question 41

Level 1 provides __ data link, but recognises individual addresses. It is Mode _ with SELCAL.

Answer 41

no C

Question 42

Level 2 provides standard data link communications in ___ direction(s)

Answer 42

both

Question 43

Level 3, 4, 5 increase the data link capabilites beyond the ___ ____ ___.

Answer 43

standard flight information

Question 44

Modes _ and _ can suffer from interference, known as fruiting and garbling

Answer 44

A C

Question 45

FRUIT stands for ___

Answer 45

False Replies and Unsynchronised to Interrogator Transmissions

Question 46

SSR equipment uses the ___ frequencies for transmitting and receiving, any interrogator can trigger any transponder within range, so any ground station can receive their replies, which appear as interference/fruit

Answer 46

same

Question 47

Garbling comes from other aircraft within ___ ___ ___ ___ responding to the same interrogation

Answer 47

line of sight range

Question 48

The length of the transponder code train is about __ microseconds, resulting in it not always being possible to decipher replies from aircraft within _ to _ miles of each other

Answer 48

2 3

Question 49

You could get overlapping returns within _._ miles

Answer 49

1.7

Question 50

___ in the decoder equipment cancel garbled replies

Answer 50

Circuits

Question 51

Mode S interrogator and receiver operate on the same frequency as the ___ ___

Answer 51

standard SSR

Question 52

A Mode S ALL CALL will be responded to by Modes ___

Answer 52

A C and S

Question 53

A Mode S transponder will respond to a Mode S ALL CALL by sending ___

Answer 53

- Aircraft ID | - Capability of all equipment on board

Question 54

Elementary surveillance will downlink:

Answer 54

- Callsign - Altitude - Transponder capabilities - Status

Question 55

Enhanced surveillance will downlink:

Answer 55

- Mag heading - IAS - TAS - MN - Vertical Rate - Roll angle - Track angle rate - True track angle - Ground speed - Selected altitude