Comms and EW Flashcards
1
Q
EM Waves are affected by what 4 behaviours?
A
Reflection
Refraction
Diffraction
Attenuation
2
Q
Define Reflection
A
Angle of incidence = Angle of reflection
3
Q
Define Refraction
A
Caused by a change of velocity as an electromagnetic wave passes from one medium to another.
4
Q
Define Diffraction
A
Deflection of waves around edges of obstacles placed in their path
5
Q
Define Attenuation
A
Reduction (fading) of a signal
6
Q
What 2 variables vary the amount of diffraction?
A
Wavelength
Size of the gap
7
Q
What do we use to refract waves in the atmosphere?
A
Ionosphere
8
Q
What do we use to refract waves in the atmosphere?
A
Ionosphere
9
Q
What propagation mechanism is used to take advantage of the ionosphere?
A
Refraction
10
Q
Describe Doppler
A
The apparent frequency shift from the point of the observer
11
Q
What is a surface wave? (Bands?)
A
Wave that follows the curvature of the Earth’s surface. Used for long distances
VLF, LF, MF to some extent
12
Q
What is a sky wave? (Bands?)
A
Wave that refracts off of the layers of the atmosphere (ionosphere). Can be used for very long distances.
HF is predominantly used due to need for refraction.
13
Q
What is a space wave? (Bands?)
A
NOT one that goes to space!
Combines LOS and Earth-reflected pathways.
VHF, UHF bands used.
14
Q
What are the effects of the atmosphere on propagation via refraction? (Pres, Moisture, Temp)
A
Pressure has no significant impact
Increase in moisture increases refraction
Decrease in Temp increases refraction
15
Q
Name the 3 different types of refraction
A
Sub-Refraction (away from surface)
Normal
Super-Refraction (towards to the surface)
16
Q
What is ducting?
A
Waves trapped between layers in the atmosphere.
Can be at ground level or at higher altitudes.
17
Q
What is scatter?
A
Regions of turbulence containing variations in refractive index, deflect small portions of energy and can be picked up.
18
Q
What are the 3 primary properties of EM wave energy
A
Wavelength
Amplitude
Frequency
19
Q
What are the EM bands (low > high Hz)
A
Radio
Microwaves
IR
Visible
UV
X-ray
Gamma Ray
Cosmic Ray
20
Q
What do radio waves consist of?
A
Oscillating electric and magnetic fields which are at right angles, or transverse to the direction of propogation.
Electrical - vertical (fingers in a plug socket, hair stands up)
Magnetic - horizontal
21
Q
….. frequency waves are more susceptible to attenuation.
A
Higher
22
Q
Describe the EM bands with frequency ranges
A
3KHz>VLF<30KHz>LF<300KHz>MF
MF<3MHz>HF<30MHz>VHF<300MHz>UHF
UHF<3GHz>SHF<30GHz>EHF<300GHz
23
Q
Sky wave is affected mostly by what 2 factors?
A
Angle of Incidence
Frequency
24
Q
Define the Maximum Useable Freq of a sky wave
A
Highest frequency at which refraction can take place at a given angle of incidence.
25
Space waves use what EM bands?
VHF, UHF
26
What is the ground wave portion of a sky wave?
Due to the width of the transmission cone, this is the ‘surface wave’ that will occur
27
What is the dead space portion of the sky wave?
The area past where by the ground wave has weakened significantly. But before where the return from the refraction of the atmosphere can be picked up.
28
What are the FREQUENICES, Types of Propagation (Surf, Sky, Space), and Uses of HF, VHF, UHF?
HF > 3-30 MHz/ SKY WAVE - single and multiple hops few thousand miles/ reliable continuous wave(CW) and radio transmission (RT)
VHF > 30-300MHz/ SPACE WAVE - within radio horizon/ Marker beacons, ILS Localizer, Radio telephone, Nav aids: VOR, PLB
UHF > 300MHz-3GHz/ SPACE WAVE - within radio horizon/ Radio telephone, ILS glide path, Pulse radio altimeters, TACAN, VORTAC, Search and GCI radars
29
What is a limitation of HF?
Noise contamination
30
What is a limitation of VHF/UHF?
Operating range - typically LOS comms.
Power has little impact on extending range
31
What is a limitation of bandwidth?
Data rate vs capacity.
This has limitations due to the power required to transmit successfully.
32
What are the 2 types of radio systems?
Guided - Wires/cables
Unguided - Waves through atmosphere
33
Describe the radio system
Message In – [Transducer] – Baseband Signal –[Modulator and Power Amp]– Aerial
Channel
Aerial–[Demodulator]–Baseband Recovered–[Transducer]–Message Out + Noise
34
How many frequencies are available and what are their spacing, in VHF and UHF?
VHF - 1300 frequencies at 8.33KHz spacing
UHF - 7000 frequencies at 25KHz spacing
35
Aircraft comms usually use what freq bands?
UHF - Military aircraft control
VHF - Civil and Military aircraft control
36
What are the 3 components of the V/UHF radio system?
Adapter Unit
Control Unit
Aerials
37
What does the ADAPTER unit do in a V/UHF radio system?
Converts data from series to parallel.
Can provide 1KHz tone.
For use in tactical situations where speech is not advisable
38
What does the CONTROL unit do in a V/UHF radio system?
Selects radio function (Tx+Rx, Tx+Rx+Guard, Tx+Rx+Homing, Tx+Rx+G+H)
Mode selection
Manual Frequency Selection
39
Why do we typically have 2 UHF aerials?
UHF may attenuate significantly across aircraft
40
Describe some points of Intercom Discipline
Mic should be off unless speaking
Monitor radio before, during and after speaking
Procedure should be followed
Crew members should NOT switch off/leave intercom without informing other crew members.
41
What is the difference between PRIMARY and SECONDARY Radar?
Primary - Operates independently of subject a/c
Secondary - A signal is used to trigger a response from equipment in the subject a/c.
42
What is the purpose of SECONDARY Radar
Used to detect and identify an a/c and determine range and bearing.
Important function in Identification of Friend or Foe (IFF).
The interrogator may be co-located with search radar or as a standalone system.
43
What is the name of the piece of equipment in the a/c that an interrogator seeks to interogate?
Transponder
44
What frequency does an interrogator interrogate at?
1030 MHz
45
What frequency will a transponder reply at when interrogated?
1090 MHz
46
A transponder provides automatic communication with who?
Air Traffic Control
47
How many possible transmit codes are available to a transponder?
4096
48
What does SSR stand for?
Secondary Surveillance Radar
49
SSR and … could be referred to as siblings?
IFF
IFF - Mil
SSR - Civvy/Mil
50
SSR (Secondary Surveillance Radar) can be degraded/ rendered inaccurate due to:
FRUITing - Friendly UnIntentional Transmission
Garbling - Multiple a/c in close proximity (Red Arrows)
Sidelobe Signals - Transponder triggered by radar sidelobes and interrogator beam.
Transponder Suppression - When the transponder is unable to respond due to it taking a very short (125 microsec) break.
51
How long are the codes that pilots set the transponder to respond with?
4 digits
52
What are the 3 SSR transponder modes?
A, C, S
53
Mode S provides a …-way data link?
TWO-way
54
Each a/c fitted with Mode S is assigned a …… address code
Unique
55
The Mode S signal, known as ‘Squitter’. Is received by ATC and who?
Other Mode S capable a/c
56
Mode S transmits information every …. second(s)?
1
57
Mode S feeds into what larger system?
Airborne Collision Avoidance System (ACAS)
58
Having unique IDs in Mode S removes what phenomena?
FRUITing and Garbling
59
What does TCAS stand for?
Traffic Alert and Call Avoidance System
60
Name the Military IFF modes.
1, 2, 3, 5
61
Name the Civilian SSR modes
A, C, S
62
Describe Mode 1
Military mode that comprise the framing pulses and information pulses set on COCKPIT control panel.
63
Describe Mode 2
Same as Mode 1. Military mode that comprise the framing pulses and information pulses.
However, NOT selectable in flight but preset on the transponder.
64
Describe Mode 3/A
Est. and maintain ID of a/c
Est. position of a/c
Facilitate hand off between ATS units
Supplement primary radar
Detect a/c squawking 7700, 7600, 7500.
65
Describe Mode C
Provides information on the vertical position of an a/c in flight
66
What are the 2 levels of Mode S?
Elementary
Enhanced Surveillance
67
Describe Mode S
Co-operative radar surveillance system employing ground-based interrogators and airborne transponders.
Evolutionary improvement to the existing SSR system in Mode3/A and C.
68
Describe Mode 5
CLASSIFIED, Mil ONLY, secure IFF system.
69
Define and describe the 3 key emergency squawk codes
7700 - Emergency situation
7600 - 2-way comms lost with ground
7500 - Unlawful interference i.e. hijacking
70
Name some examples of Link Units
Ground Stn
Reconnaissance a/c or unit
Offensive a/c or unit
AWACS a/c
Capital Ships
71
What are the 3 types of EW?
Electronic Support Measures (ESM)
Electronic Attack (EA)
Electronic Protection (EP)
72
What does ESM stand for?
Electronic Support Measures
73
What does EA stand for?
Electronic Attack
74
What does EP stand for?
Electronic Protection
75
What does RWR stand for?
Radar Warning Receiver
76
Describe Range Advantage
The ability of you radar to see an object before it sees you
77
The RWR provides you with…
Range Advantage
Direction Finding
78
An RWR uses what techniques to determine direction?
Amplitude and Phase comparisons
79
Within EA we have ECM. What does ECM stand for?
Electronic Counter Measures
80
ECM is used to _____ the effectiveness of a radar
REDUCE the effectiveness
81
ECM techniques can fall under 2 categories. These are…
Electronic Jamming
Electronic Deception
82
Define Electronic Deception
Deliberate radiation, re-radiation, alteration, absorption or reflection of EM energy.
Done to confuse, distract, or seduce an enemy or their systems.
83
List some means of Electronic Deception
Decoys
Chaff
Tactics
Stealth
IR Countermeasures
84
Electronic Protection (EP) is all about making it as _____ and as _____ as possible for an adversary to have an impact on your operations.
DIFFICULT and as COSTLY as possible
85
EP is provided by …
Freq Agility
SOPs
Equipment Design
Parallel Ops
Planning
86
To reduce the effectiveness of an incoming threat. Your deception signals need to be accepted by the adversaries missile’s ______.
Receiver
87
ESM is used to _____, ______ and _____ sources of intentional and ________ radiated EM energy.
ESM is used to INTERCEPT, IDENTIFY and LOCATE sources of intentional and UNINTENTIONAL radiated EM energy.
88
What factors affect Radar Cross Section?
Shape
Size
Aspect
Build Materials
89
The aim of the IR jammer is to ….
….disrupt the modulated signal coming from the IR missile so as to cause errors in the missile guidance.
90
EP involves all actions taken to ______ ______, ______ and ______ from any effects of friendly, or enemy, employment of EW that ______, ______ or ______ friendly combat capability.
EP involves all actions taken to PROTECT PERSONNEL, FACILITIES and EQUIPMENT from any effects of friendly, or enemy, employment of EW that DEGRADE, NEUTRALIZE or DESTROY friendly combat capability.
91
Reducing RCS seeks to minimise the amount of …..
RADAR ENERGY reflected back towards to radar.
92
The aim of IR decoys is to …..
present a target to the missile that is more compelling than the a/c.
93
What does DIRCM stand for?
Directional Infra Red Countermeasures
94
How does DIRCM work?
Detects incoming missile with Missile Warning System (MWS).
IRCM head applies false signal to missile.
False signal jams missile guidance.
A/C no longer in missile FOV.
95
What is the purpose of the ground marshallers?
To ensure a/c are manoeuvred safely on the ground
96
When marshalled on the ground, who is responsible for the safety of the a/c?
The a/c commander is always responsible for the safety of the a/c
97
Describe the AFFIRMATIVE signal?
Thumbs Up
98
Describe the NEGATIVE signal?
Thumbs Down
99
Describe the STOP signal?
Crossed arms above head
100
Describe the THIS WAY signal?
Straight arms raised above head
101
Describe the PROCEED TO NEXT MARSHALLER signal?
Arms pointing/moved towards the direction of the next marshaller.
102
Describe the CONNECT ELECTRICAL POWER signal?
Two fingers into fist
103
Describe the DISCONNECT ELECTRICAL POWER signal?
Two fingers out of fist
104
Describe the START ENGINE signal?
Arms above head.
Left hand of marshaller Fingers/flashes indicating engine number.
Right hand of marshaller. Around in circle.
105
Describe the CUT ENGINE signal?
Chop across neck
106
Describe the FIRE signal?
Infinity symbol in one hand and pointing towards fire with other
107
Describe the FLAPS LOWER signal?
Open flat hands apart
108
Describe the FLAPS RAISE signal?
Close flat hands together
109
Describe the CHOCKS IN signal?
Bring hands and thumbs (pointing in) together at 6 o'clock
110
Describe the CHOCKS OUT signal?
Move hands and thumbs (pointing out) apart from 6 o'clock
111
Describe the MOVE AHEAD signal?
Both arms straight out in front then brought towards the body
112
Describe the SLOW DOWN signal?
Hands moved in a downwards direction with palms facing down
113
Describe the TURN LEFT signal?
Marshaller’s right hand pointing to your left with other moving in direction required.
114
Describe the TURN RIGHT signal?
Marshaller’s left hand pointing to your right with other moving in direction required.
115
Describe the BRAKES ON signal?
Closing fists with arms out front
116
Describe the BRAKES OFF signal?
Opening fists with arms out front
117
Describe the REQUEST TO MOVE PERSONNEL TOWARDS A/C signal?
One arm pointing towards personnel and other straight in the air
118
Describe the CLEARANCE TO MOVE PERSONNEL TOWARDS A/C signal?
A/c commander single arm towards face. Palm to face.
119
“Chop across neck” indicates what signal?
CUT ENGINE
120
“Thumbs down” indicates what signal?
NEGATIVE
121
“Crossed arms above head” indicates what signal?
STOP
122
What are the “actions on” if visual is lost with the ground marshall?
STOP immediately and seek further assistance
123
Name the 3 types of radiotelephony transmissions
Clearance
Instructions
Information
124
What time reference should be used unless told otherwise?
UTC
125
What is the PROWORD for
“True or Accurate”?
CORRECT
126
What is the PROWORD for
“I wish to know or obtain”?
REQUEST
127
What is the PROWORD for
“Taxi on active runway in opposite direction to use”?
BACKTRACK
128
What is the PROWORD for
“What’s the readability of my transmission”?
HOW DO YOU READ
129
What is the range of the readability scale?
1-5
130
What is the PROWORD for
“Yes”
AFFIRM
131
What is the PROWORD for
“No”
NEGATIVE
132
What is the PROWORD for
“I repeat for clarity or emphasis”
I SAY AGAIN
133
What is the PROWORD for
“Ignore”
DISREGARD
134
What is the PROWORD for
“I have finished transmitting and don’t expect a response”
OUT
135
What is the PROWORD for
“Verify something is correct”
CONFIRM
136
What is the PROWORD for
“I have received and understood last transmission”
ROGER
137
What is the PROWORD for
“Let me know you received and understood message”
ACKNOWLEDGE
138
What is the PROWORD for
“Establish contact with next ATC unit. Your details have been passed”
CONTACT
139
What is the PROWORD for
“A formal handover has not been arranged, your details have not been passed”
FREECALL
140
The suffix CONTROL refers to what type of service?
CONTROL - Area Control
141
The suffix RADAR refers to what type of service?
RADAR - Radar (in general)
142
The suffix APPROACH refers to what type of service?
APPROACH - Approach Control
143
The suffix TOWER refers to what type of service?
TOWER - Aerodrome Control
144
The suffix DEPARTURE refers to what type of service?
DEPARTURE - Approach Control Radar Departure
145
The suffix GROUND refers to what type of service?
GROUND - Ground Movement Control
146
The suffix ZONE refers to what type of service?
ZONE - Military Aerodrome Traffic Zone (MATZ) crossing
147
The suffix TALKDOWN refers to what type of service?
TALKDOWN - Precision Approach Radar
148
The suffix INFORMATION refers to what type of service?
INFORMATION - Flight Information
149
The suffix RADIO refers to what type of service?
RADIO - Air/Ground Communication Service
150
The suffix DELIVERY refers to what type of service?
DELIVERY - Clearance Delivery
151
List good RT Techniques
Receiver Vol set to optimum level
Freq check for interference
Mic correct distance from mouth
NORMAL tone
Steady speech rate
Constant volume
PAUSE before and after numbers
No hesitations or ‘er’s
No excessive use of courtesies
Ensure push to talk depressed
Use standard R/F words and phrases
152
Emergencies can happen where?
On the ground
In the Air
Without Warning
153
If an emergency occurs, follow what 3 word rule of thumb?
Aviate, Navigate, Communicate
154
What frequencies are used for emergencies?
121.5 MHz
243. 0 MHz
155
Name the 3 standard emergency Mode 3/A squawks
7700 - Emergency
7600 - Total Radio Failure
7500 - Unlawful Interference
156
What single word does “MAYDAY MAYDAY MAYDAY” indicates?
Distress
157
What single word does “PANPAN PANPAN PANPAN” indicates?
Urgency
158
Describe what “MAYDAY MAYDAY MAYDAY” conveys?
Distress - A/c is threatened by serious or imminent danger requiring immediate assistance
159
Describe what “PANPAN PANPAN PANPAN” conveys?
Urgency - Safety concern for a/c, other vehicle or pax but not requiring immediate assistance
160
In an emergency transmission you should include what information?
Callsign
Type of a/c
Nature of emergency
Captain’s intentions and assistance required
Present or last known position, level and heading
Pilot quals (if relevant)
Any other information
161
“Securite Securite Securite” is used for what purpose?
Inform all air traffic that a message contains info affecting safety
162
What is the distance between the Tx (Transmitter) and Rx (Receiver) known as?
Skip distance
163
What do EM waves consist of?
Electric + Magnetic Field
164
What function on the intercom station box can be set to bypass the press to talk switch?
Hotmic
165
What part of the crew comms system (CCS) is provided at each of the principal crew stations and permits individuals to select Tx and Rx as required?
Intercom Stn Box
166
What frequencies does IFF/SSR use?
1030 MHz - Interrogate
1090 MHz - Transponder
167
Why was Mode S introduced?
Support the automation of Air Traffic systems
168
Which Mil IFF and Civ SSR modes are the same?
Mil Mode 3
Civ Mode A
169
Which Mil IFF modes can be set in the cockpit?
Mode 1 + Mode 3
170
What are the 3 types of EW?
ESM, EA, EP
171
What is the name for actions taken to intercept, identify and locate intentional and unintentional radiated EM energy?
ESM
172
What is the name for actions taken to prevent or reduce an enemy’s effective use of the EM spectrum, such as jamming and EM deception?
EA
173
What equipment is designated to detect, localize and identify threat radars so that appropriate countermeasures can be taken?
RWR - Radar Warning Receiver
174
What is designed and programmed to identify threats, give warning to the crew and, where available, generate countermeasures?
Defensive Aid Suite (DAS)
175
List some examples of possible measures that provide Electronic Protection?
Planning
Equipment Design
Frequency Diversity and Agility
Spread Spectrum
