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Flashcards in Radar | Secondary Surveillance Radar Deck (55)
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1
Q

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

A

double

2
Q

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

A

pulse

3
Q

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

A

1030 Mhz, 1090 MHz

4
Q

The interrogation and response pulses are ___ _Hz apart

A

60 Mhz

5
Q

Primary radar is ___ accurate in terms of bearing and distance

A

more

6
Q

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

A

Downlink Additional Parameters - DAP

7
Q

Mode 3/A asks ____

A

who are you?

8
Q

Mode C asks ___

A

how high are you?

9
Q

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

A

control

10
Q

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

A

interrogation

11
Q

A spacing for transmission and reception is called a ___

A

mode

12
Q

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

A

P1 P3

13
Q

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

A

shorter, longer

14
Q

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

A

weaker

15
Q

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.

A

P1 and P3, P2

16
Q

Mode S uses a short __ pulse

A

P4

17
Q

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

A

Mode A/C/S all call

18
Q

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

A

IDENT

19
Q

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.

A

14 8 17 F1 F2 12 4096

20
Q

The IDENT pulse is transmitted for up to __ seconds

A

20

21
Q

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

A

3, A, B, C, D

22
Q

Selecting 2300 would produce the codes ___

A

010
110
000
000

23
Q

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

A

no, 2

24
Q

Mode C is just Mode _ plus altitude reporting

A

A

25
Q

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

A

100

26
Q

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

A

50 300

27
Q

Mode C pulses are __ microseconds apart

A

21

28
Q

The S in Mode S stands for ___

A

selective

29
Q

Mode S pulses are __ microseconds apart

A

25

30
Q

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

A

all

31
Q

Mode S provides altitude reporting in __ft intervals

A

25

32
Q

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

A

long 112

33
Q

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

A

24

34
Q

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

A

P1 P3 long P4

35
Q

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

A

P2, P1

36
Q

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

A

P1 P3 short P4

37
Q

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

A

receiving request

38
Q

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

A

1030 1090 MHz

39
Q

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

A

5700 250

40
Q

The two main functions of a Mode S transponder are __

A
  • G/A and A/G data link

- Improved ATC aircraft surveillance capability

41
Q

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

A

no C

42
Q

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

A

both

43
Q

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

A

standard flight information

44
Q

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

A

A C

45
Q

FRUIT stands for ___

A

False Replies and Unsynchronised to Interrogator Transmissions

46
Q

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

A

same

47
Q

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

A

line of sight range

48
Q

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

A

2 3

49
Q

You could get overlapping returns within . miles

A

1.7

50
Q

___ in the decoder equipment cancel garbled replies

A

Circuits

51
Q

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

A

standard SSR

52
Q

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

A

A C and S

53
Q

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

A
  • Aircraft ID

- Capability of all equipment on board

54
Q

Elementary surveillance will downlink:

A
  • Callsign
  • Altitude
  • Transponder capabilities
  • Status
55
Q

Enhanced surveillance will downlink:

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