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Comm Prog (05 Oct 2012) > Comm 1-11 > Flashcards

Comm 1-11 Flashcards

1
Q

Why Comms are important?

A
  • Primary mean for Command and Control (C2)
  • Monitor ATC comms and assist pilots
  • Responsible for most Tac comms on CF aircrafts
  • Responsible for airborne communication jamming ops
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2
Q

Wavelength (ג) definition

A

The distance between two successive points on an EM wave. Measured in meters (m).

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3
Q

Frequency (f) definition

A

The number of times the cycle of an EM wave is repeated in one second. Measured in cycles/second, ie Hertz (Hz).

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4
Q

Speed of Light (c) definition

A

the speed at which EM waves propagate through a vacuum. (3 x 108 m/s)

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5
Q

Describe the different Frequency terms & abbreviations

A

1 hertz = 1 cyc/sec = 1Hz
1 kilohertz = 1000 cyc/sec = 1 KHz = 1000 Hz
1 megahertz = 1 000 000 cyc/sec = 1 MHz = 1000 KHz
1 gigahertz = 1 000 000 000 cyc/sec = 1 GHz = 1000 MHz

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6
Q

Wavelenght/Frequency relationship can be expressed as:

A

c = f ג

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7
Q

Radio Frequency (RF) Spectrum

A

FREQUENCY BAND FREQUENCY RANGE WAVELENGTH RANGE
Very Low Freq (VL) 3-30 KHz 100 000 – 10 000m
Low Freq (LF) 30-300 KHz 10 000 – 1000m
Medium Freq (MF) 300-3000 KHz 1000 – 100m
High Freq (HF) (Short-wave radio) 3-30 MHz 100 – 10m
Very High Freq (VHF) ((CIVILIAN)) 30-300 MHz 10 – 1m
Ultra High Freq (UHF) ((MILITARY)) 300-3000 MHz 1m – 10cm
Super High Freq (SHF) 3-30 GHz 10 – 1cm

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8
Q

Uses of VLF

A

Time signals, standard frequencies, (used for scientific and technical purposes)

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9
Q

Uses of LF & MF

A

Navigational aid, radio broadcasting station, ship-to-shore station

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10
Q

Uses of HF

A

Maritime and aeronautical comms, long range radio broadcasting (time, weather, etc)

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11
Q

Uses of VHF

A

Maritime and aeronautical comms, amateur, radio and TV broadcasting, navigational aid, radio locator

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12
Q

Uses of UHF

A

Maritime and aeronautical comms, amateur, TV Broadcasting, radio locator, meteorological info, satellite comms

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13
Q

Uses of SHF

A

Satellite radio and data comms, TV, etc

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14
Q

What are the 2 components of radio waves

A

1) Electrical

2) Magnetic

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15
Q

Define Radio waves

A

Radio waves are electromagnetic (EM) waves. They are differentiated from other EM energy by frequency.

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16
Q

Characteristics of Radio Waves and EM energy

A
  • RF or EM energy requires no supporting medium: Radio waves will propagate through a vacuum. They propagate at the speed of light (3 x 108 m/s) in a vacuum.
  • It can penetrate gases, liquids and solids: Different frequencies will be affected differently by various media.
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17
Q

Factors Affecting Propagation

A 
Polarization   
Frequency & Wavelength
Refraction
Reflexion
Diffraction
Attenuation

People Find Rare Rubies Dusting Attics

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18
Q

How Polarization affect propagation?

A

Refers to the orientation of the E-field of the wave with respect to the earth’s surface.
(same orientation = better)

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19
Q

How Frequency and Wavelength affect propagation?

A

Inversely proportional.
Low Frequency/Long wavelength
High Frequency/Short wavelength

High freq = better fidelity.

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20
Q

How Refraction affect propagation?

A

Change in direction of a radio wave caused by it’s change in velocity as it passes from one medium to another.

The amount that the radio wave will bend depends on :

1) index of refraction
2) frequency of the wave
3) angle of incidence

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21
Q

How Reflection affect propagation?

A

Bouncing of radio waves off an object which has a different density than the propagating medium.

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22
Q

How Diffraction affect propagation?

A
  • When a wave grazes a solid object, some of the energy is diverted toward the object.
  • Once past the object, energy continues to propagate in the new direction.
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23
Q

How Attenuation affect propagation?

A

loss of EM energy as the wave moves away from the source.

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24
Q

Attenuation is caused by what?

A 
Spreading
Absorbtion
Scattering
Refraction
Diffraction

Savin Apple Seeds Requires Dirt

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25
Q

How Spreading cause attenuation?

A

From a non-directional antenna, energy is transmitted in all directions. As it moves away, it must cover an ever increasing area.

1w @ 1 nm // 1/10exp2 w @ 10 nm

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26
Q

How Absorption cause attenuation?

A

As a radio wave passes through a medium, some energy is loss to surrounding molecules in the form of heat.

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27
Q

How Scattering cause attenuation?

A

by object in propagation path.

28
Q

How Refraction cause attenuation?

A

Change in direction of a radio wave caused by it’s change in velocity as it passes from one medium to another.

The amount that the radio wave will bend depends on :

1) index of refraction
2) frequency of the wave
3) angle of incidence

29
Q

How Diffraction cause attenuation?

A
  • When a wave grazes a solid object, some of the energy is diverted toward the object.
  • Once past the object, energy continues to propagate in the new direction.
30
Q

Name the 3 Propagation Paths

A

1) Ground Wave
2) Tropospheric Wave Ducting
3) Sky Wave

31
Q

Define Ground Wave

A

Portion of radiated energy that is directly affected by the earth and it’s surface features.

2 Components:

1) Surface wave (max range in the MF and low HF bands is 100nm
2) Space wave (150-200nm)

32
Q

Define Tropospheric Wave Ducting

A

Refraction + Reflection in lower levels of the atmosphere. It’s caused by abrupt changes in temperature and moisture

  • most noticeable in VHF and lower UHF bands
  • More effect as the freq of the signal increase
33
Q

Define Sky Wave

A

refraction in upper atmosphere. Occurs in the MF and HF frequency bands. Gives reliable comms over very long distances.

34
Q

Comms system are designed to Tx info from one point to another. What are the 3 basic parts?

A

1) Transmitter
2) Receiver
3) Antennas

35
Q

What are the specifications of the VHF Radio on the Dash-8?

A

Specifications:

1) AM
2) 118.000 to 151.975 MHz**
3) 25 KHz spacing
4) LOS
5) Low Power (< 26 w)**
6) Quiet + static free
7) Almost unaffected by WX
8) Memory for 9 preset channels.**

36
Q

What are the components of the VHF Radio on the Dash-8?

A

Components:

1) 2xVHF Control Display Units (CDUs)
2) 2x Receiver/Transmitters
3) VHF/UHF antenna for #1 system (Top)
4) VHF antenna for #2 system (Bottom)

37
Q

What are the different call to make on VHF?

A

Wops: (131.4 MHz)

1) Taxi advisory (After E/ON)
2) Airborne (Cleared + above safety height)
3) Inbound (20 min before landing: ETA, SOB, Fuel, Serviceable)
4) Taxiing in (once clear of active Rwy, request parking spot

Others:

1) Air to Air
2) Wx
3) ATC + FSS

38
Q

What is the procedure for making calls?

A

Making radio calls:

1) Confirm freq with pilot
2) Tell crew going out on VHF
3) Make call
4) Tell crew back on ICS
5) Pass any instructions to pilot

39
Q

What do we need to log?

A

Things to LOG:

1) ATIS
2) VFR/IFR Clx requests
3) Taxi clx
4) Departure/enroute+arrival clxs
5) Wx requests with FISE

40
Q

How to request Weather?

A

Requesting Weather:

1) Making sure a FISE exists (not shared by MF/ATF & 2 or more decimals)
2) Requesting the actual and amendments only to the 18Z forecast for Winnipeg and Brandon (destination + alternate)

41
Q

What are the specifications of the UHF Radio on the Dash-8?

A

Specifications:

1) AM
2) 225.000 to 399.975 MHz**
3) 25 KHz spacing
4) LOS
5) 28 V DC**
6) Small, light, quiet, static-free
7) Unaffected by WX
8) Memory for 20 preset channels**

42
Q

What are the components of the UHF Radio on the Dash-8?

A

Components:

1) 2x Transceivers (Cockpit, centre pedestral, aft of power levers)
a. 1 for Tx/Rx
b. 1 for guard (Rx only) 243.000MHz
2) 1 Control head (located with transceivers)
3) 2 Antennas (Top – VHF #1 shared and Bottom – VHF/UHF DF)

**To monitor guard while working on the Ops freq, select “BOTH” on the freq selector

43
Q

What are the different call to make on UHF?

A

1) request for Start Crew @ WOps(308.8 MHz)
2) Air to Air : other Gonzos (G5, G6, by route 3 TP A @ 100O ft AGL, time 1934Z
3) Wx request

44
Q

Other UHF users?

A

Other UHF users:

1) RCMP
2) Ships
3) Cellphones
4) Coast Guard
5) RCC’S

45
Q

Name the TYPICAL FLIGHT calls (Internal + External calls)

A 
A.ATIS
1) Start crew* (SOB, Fuel)
B. Pre-Start check
C. Engine Start check
D. Pre-Taxi Check
2) Clx delivery
3) Taxi Clx
4) Taxi advisory* (E/ON time, taxiing)
5) Take off clearance
6) Airborne call* (A/B time, ETA)
7) Blind Broadcast
8) UHF Air to air
**LOG all other ATC clearance**
9) Inbound call *(ETA, SOB, Fuel, Servc.)
10) Taxi in* (request parking spot)
*=WOps
46
Q

On the radio, always listen to…

A

Ctrl Freqs /ATC Clearances
Ground Tx’s from MFs/UNICOMS
Blind Broadcasts
UHF sitreps from other GONZOs

47
Q

What does SLIC mean?

A

Stop
Listen
Identify
Continue

48
Q

Name some ways to identify objects

A

1) Description
2) Direction (Clock)
3) High/Low indication
4) Distance
5) ‘‘no conflict’’ or conflict with instructions

49
Q

Describe the Emergency audio integration mode

A

Pilot: VHF 1(and mic) & VOR 1 (audio)
CO/FE: VHF 2 (and mic) & VOR 2 (audio)

Other ways: Runners, hand signals, notes, etc

50
Q

Name 3 other forms of modulation (other then Amplitude modulation & Frequency modulation)

A

1) Phase modulation (for digital signals)
2) Pulse modulation (carrier is a train of pulses (morse code))
3) Frequency Shift Keying ( frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave)

51
Q

What are the DESIRABLE Rx Functions?

A

1) INTERCEPT some of RF energy from Transmitter
2) SELECT correct RF from multitude of signals
3) DETECT + SEPARATE intelligence from carrier
4) reproduce intelligence into some MEANINGFUL form

52
Q

What are the Rx Characteristics?

A

1) Frequency Coverage: Rx optimized for specific freq bands.
2) Sensitivity: ability to intercept weak signals
3) Selectivity: ability to extract intel + exclude unwanted signals
4) Fidelity: reproduce Tx’d intelligence (more req’d for data than voice)

53
Q

Define antenna gain

A

The measurement of an antenna’s ability to radiate energy in a particular direction.

Gain is a function of antenna size and shape

54
Q

Define antenna polarization

A

Orientation of the Tx antenna that determines the orientation of the wave. Receiving antenna must have a similar polarization as the wave they are receiving in order to intercept it efficiently.

55
Q

Define Receiving antenna (Rx antenna)

A

The EM waves from the transmitting antenna excite the electrons in the receiving antenna.

This cause an electric current to be formed and conducted to the receiver.

56
Q

Define Transmitting Antenna (Tx antenna)

A

Contains charges that oscillate at the desired frequency.

The oscillation causes EM waves to be formed and radiated away from the antenna.

57
Q

Amplitude modulation YOUTUBE

A

http://www.youtube.com/watch?v=3ZMPcPR7W3Q

58
Q

Frequency modulation YOUTUBE

A

http://www.youtube.com/watch?NR=1&feature=endscreen&v=ens-sChK1F0

59
Q

Amplitude modulation (AM) advantages

A

Simpler equipment
Less bandwidth
Better range (FM = LOS)

60
Q

Frequency modulation (FM) advantages

A

SNR
Fidelity
Ppeak constant

61
Q

Define Amplitude Modulation

A

Amplitude of a carrier is increase or decrease in accordance with the signal to be conveyed.

62
Q

Define Frequency Modulation

A

Frequency of carrier is modified to reflect changes in audio signal to be conveyed.

Loudness (amplitude) of audio signal determines the amount of frequency change.

Pitch (frequency) determines the rate the carrier is affected.

63
Q

Why is modulation required?

A

1) Size: low freq ( voice @ 200Hz to 3 KHz) require large parts
2) Interference: to not transmit on the same freq
3) Propagation REQs: use RF band in accordance

64
Q

Name the 4 parts of the Transmitter

A

Radio Frequency Section:

1) Oscillator Generator (generate carrier wave…Freq.=constant)
2) Amplifiers (Increases signal power for transmission)

Modulator Section:

3) Information
4) Modulator (Impresses intelligence onto the carrier wave

65
Q

Name the 3 parts of the Receiver

A

Selective Circuit —-> Detector ——>Audio Amplifiers

Comm Prog (05 Oct 2012) (1 decks)

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