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ET1 SEP EXAM 2018 > NAVEDTRA 14189A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES. MODULE 17- RADIO-FREQUENCY COMMUNICATIONS PRINCIPLES > Flashcards

NAVEDTRA 14189A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES. MODULE 17- RADIO-FREQUENCY COMMUNICATIONS PRINCIPLES Flashcards

1
Q

What year was the first official naval radio message sent from ship to shore?

A

1899

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2
Q

What year was the first radiotelephone used between ships?

A

1916

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3
Q

In what year were the first superheterodyne receivers installed in the fleet?

A

1931

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4
Q

In what year were the first successful radio teletypewriter transmissions between ships completed?

A

1944

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5
Q

In what year did the first successful use of radiophoto (facsimile) occur?

A

1945

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6
Q

What refers to communications over a distance and includes any transmission, emission, or reception of signs, signals, writings, images, or sounds?

A

Telecommunications

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7
Q

What is the most important method the Navy has of communicating between widely separated forces?

A

Radio

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8
Q

What was the first means of radio communications that had military and commercial importance?

A

Radiotelegraphy

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9
Q

Line-of-sight characteristics limit the usual range of radiotelephone from how many miles?

A

20-25

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10
Q

The Navy uses radio teletypewriter (rtty) mainly for high-speed automatic communications across ocean areas and has a normal speed of operation of how many words per minute?

A

100

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11
Q

What is the process used to transmit photographs, charts, and other graphic information electronically?

A

Facsimile (fax)

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12
Q

What is a combination of sets, units, assemblies, subassemblies, and parts joined together to perform a specific operational function or several functions?

A

System

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13
Q

What consists of a unit or units and the assemblies, subassemblies, and parts connected or associated together to perform a specific function?

A

Set

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14
Q

What is a collection of units, assemblies, subassemblies, and parts?

A

Group

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15
Q

What is an assembly or any combination of parts, subassemblies, and assemblies mounted together?

A

Unit

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16
Q

What is a number of parts or subassemblies, or any combination thereof, joined together to perform a specific function?

A

Assembly

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17
Q

What is one component or two or more components joined together?

A

Part

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18
Q

What is the frequency range for the extremely high frequency (EHF) band?

A

30 GHz-300GHz

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19
Q

What is the frequency range for the super high frequency (SHF) band?

A

3GHz-30GHz

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20
Q

What is the frequency range for the ultra high frequency (UHF) band?

A

300MHz-3GHz

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21
Q

What is the frequency range for the very high frequency (VHF) band?

A

30MHz-300MHz

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22
Q

What is the frequency range for the high frequency (HF) band?

A

3MHz-30MHz

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23
Q

What is the frequency range for the medium frequency (MF) band?

A

300KHz-3MHz

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24
Q

What is the frequency range for the low frequency (LF) band?

A

30 KHz-300KHz

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25
Q

What is the frequency range for the very low frequency (VLF) band?

A

3KHz-30KHz

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26
Q

What is the frequency range for the extremely low frequency (ELF) band?

A

Up to 300Hz

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27
Q

What band has the ability to penetrate ocean depths to several hundred feet with little signal loss?

A

ELF

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28
Q

What type of transmission is normally considered a broadcast, that is, one-way transmission, no reply required?

A

VLF

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29
Q

What systems are established to communicate over long-distance trunks or links between fixed terminals?

A

Point-to-point

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30
Q

What is normally a message circuit between two points that are both switching centers or individual message distribution points?

A

Trunk

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31
Q

What is a transmitter-receiver system connecting two locations?

A

Link

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32
Q

Frequencies above what are not normally refracted by the atmosphere and ground-wave range is minimal?

A

30 megahertz

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33
Q

The naval communications system is broken down into what groups?

A

Strategic and tactical

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34
Q

What type of communications are usually limited to a specific area of operations and are used to direct or report the movement of specific forces?

A

Tactical

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35
Q

What mode is a method of operation in which telecommunications between stations takes place simultaneously in both directions using two separate frequencies?

A

Full-Duplex (fdx)

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36
Q

What is the type of operation in which one station transmits information on one or more channels directed to more than one station and/or unit?

A

Broadcast (bc)

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37
Q

Message traffic is normally sent to the fleet by three methods: broadcast, intercept, and what else?

A

Receipt

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38
Q

What combines into a single system all the elements that make up the naval communications system and the Army and Air Force equivalent?

A

DCS

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39
Q

What offers rapid, direct interconnection of DOD and certain other government installations through worldwide telephone exchanges?

A

DCS AUTOVON

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40
Q

What provides authorized users with a means for exchanging classified information over communications security (COMSEC) circuitry or over other approved circuitry?

A

AUTOSEVOCOM

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41
Q

Daily capacity of the AUTODIN system is about how many average-length messages?

A

Five million

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42
Q

What was established for the purpose of integrating the critical intelligence communications (CRITICOMM) and the special intelligence communications (SPINTCOMM) networks into a single automated communications network?

A

DSSCS

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43
Q

What network provides a voice link between the Chief of Naval Operations (CNO) and all subordinate commands ashore, afloat, and airborne?

A

HICOM

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44
Q

What meets our need for a connection between Navy tactical voice systems of the operating forces and the various fixed telephone services ashore?

A

NORATS

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45
Q

What is the principle use of the continuous wave?

A

Radiotelegraphy

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46
Q

A cw transmitter requires four essential components. These are a generator, amplified, keyer, and what else?

A

Antenna

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47
Q

What is power the product of?

A

Current and Voltage

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48
Q

What refers to a sine wave quantity (for example, an oscillator output) that has a frequency that is a submultiple of the frequency of some other sine wave quantity it helped make?

A

Subharmonic

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49
Q

What are special power amplifiers that multiply the input frequency?

A

Frequency multipliers

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50
Q

What is the elimination of the undesired portions of the signal?

A

Suppression

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51
Q

What type of transmission is the most common communications mode used today?

A

Single-sideband

52
Q

What is generally used whenever special voice communications circuits are necessary between shore activities or between ships and shore activities because it is less susceptible to atmospheric interference than amplitude modulation?

A

SSB

53
Q

What is used extensively in naval communications to expand out traffic capabilities?

A

ISB

54
Q

What four basic functions must a receiver perform in order to be useful?

A

Reception, selection, detection, and reproduction

55
Q

What occurs when a transmitted electromagnetic wave passes through the receiver antenna and induces a voltage in the antenna?

A

Reception

56
Q

What is the ability of the receiver to select a particular frequency of a station from all other station frequencies appearing at the antenna of the receiver?

A

Selection

57
Q

What is the action of separating the low (audio) frequency intelligence from the high (radio) frequency carrier?

A

Detection

58
Q

What is the action of converting the electrical signals to sound waves?

A

Reproduction

59
Q

What property is defined by the ability of a receiver to reproduce weak signals?

A

Sensitivity

60
Q

What is the limiting factor of sensitivity?

A

Noise

61
Q

What is the degree of distinction made by the receiver between the desired signal and unwanted signals?

A

Selectivity

62
Q

What property of a receiver is its ability to accurately reproduce, in its output, the signal that appears at its input?

A

Fidelity

63
Q

What is the process used to tune two or more circuits with a single control?

A

Ganged tuning

64
Q

What are the only two fundamental sections of the fm receiver that are electrically different from the AM receiver?

A

Discriminator and Limiter

65
Q

Which circuit in FM circuits is designed to respond to frequency shift variations?

A

Discriminator

66
Q

What is the variation in signal strength called at the receiver antenna?

A

Fading

67
Q

What is an AGC voltage that is used to cause degeneration by driving the amplifiers toward cutoff referred to as?

A

Reverse AGC

68
Q

Which audio amplifier property determines the degree of amplification provided to different frequencies in the sound spectrum?

A

Frequency response

69
Q

Treble tones are defined as the audio frequencies above approximately what frequency?

A

3,000 hertz

70
Q

Bass tones are defined as the audio frequencies below approximately what frequency?

A

300 hertz

71
Q

Which circuits are used in situations where you must accurately control the frequency of an oscillator by some external signal?

A

Automatic Frequency Control

72
Q

Which circuit cuts off the output of a receiver when there is no input?

A

Squelch

73
Q

What is a signal-producing process through heterodyning and frequency selection?

A

Frequency synthesis

74
Q

What provides the capability to transfer remote control station functions and signals to transmitters?

A

Transmitter transfer switchboard

75
Q

What is the most widely used code in manual telegraphy?

A

Morse code

76
Q

The interval between words is equal to how many dots in morse code?

A

Seven

77
Q

The five-unit (five-level) code has been the most commonly used in modern printing telegraphy and is universally used in teletypewriter operation. This is also known as what code?

A

Baudot

78
Q

What are the two basic modes of teletypewriter operation?

A

Asynchronous and Synchronous

79
Q

What is the most common mode used in teletypewriter operation?

A

Start-stop

80
Q

What is the reciprocal of the time in seconds of the shortest signal element?

A

Baud rate

81
Q

How many words per minute is the defense communications system standard speed for teletypewriter operation?

A

100

82
Q

Which type of circuits make sue of the presence or absence of current flow to convey information?

A

Neutral

83
Q

Under which condition does the teletypewriter appear to be running because the machine is decoding the constant space as the Baudot character blank and the type hammer continually strikes the type box but there is no printing or type box movement across the page?

A

Running open

84
Q

Which two basic radio teletypewriter (ratt) systems does the Navy use?

A

Tone modulated and Carrier Frequency Shift

85
Q

Which colors are used on patch panels to identify whether that panel is used for passing secure or non-secure information?

A

Red and Black

86
Q

Which type of equipment is used to encrypt and decrypt tty messages that require security handling?

A

Cryptographic

87
Q

What takes the rf signal passed on by the antenna filter and translates it to an audio signal?

A

Radio receiver

88
Q

What is a combined, simultaneous display of the amplitude and phase relationships of two input signals?

A

Lissajous pattern

89
Q

Which type of communications circuit permits two-way communications between stations?

A

Half-duplex

90
Q

What is the simultaneous transmission of a number of intelligible signals (messages) in either or both directions called using only a single rf carrier?

A

Multiplexing

91
Q

Which two methods of multiplexing can be used?

A

Time-division and Frequency-division

92
Q

What is the normal voice speaking frequency range?

A

100 to 3,500 hertz

93
Q

By multiplexing tty circuits, up to how many circuits may be carried in any one of the 3,000 hertz multiplexed channels?

A

16

94
Q

Which transmission method is used for transmitting still images over an electrical communications system?

A

Facsimile

95
Q

What are compromising emanations (ce) generally referred to as?

A

Tempest

96
Q

What includes all measures designed to protect transmission from interception, traffic analysis, and imitative deception?

A

Transmission security

97
Q

What occurs when a person comes into contact with a source of rf voltage in a manner that allows rf current to flow through the area of contact?

A

RF burn

98
Q

Which device changes dc pulses to mark and space modulation for teletypewriter transmissions?

A

Keyer

99
Q

What changes an audio signal back to dc pulses during teletypewriter reception?

A

Converter

100
Q

Which device stores a teletypewriter message on a paper tape by punching Baudot coded messages into it?

A

Perforator

101
Q

What stores an incoming tty signal on paper tape?

A

Reperforator

102
Q

What is the reference color of equipment that passes classified information?

A

Red

103
Q

Which year was the first artificial satellite placed in orbit by the Russians?

A

1957

104
Q

Score was the first satellite with the primary purpose of communications by the US in which year?

A

1958

105
Q

Which year was the first regular satellite communications service used by the Navy?

A

1960

106
Q

Which year was the Defense Communications Satellite Program (DCSP) initiated by the Secretary of Defense?

A

1962

107
Q

Which type of satellite only reflects received radio signals back to earth?

A

Passive

108
Q

What amplifies signals received and then retransmits them back to earth?

A

Repeater

109
Q

In general terms, an orbit is either elliptical or which other shape?

A

Circular

110
Q

What is a period of orbit that approaches that of the earth called?

A

Near synchronous

111
Q

All satellites orbit the earth in which type of orbits?

A

Elliptical

112
Q

What is the point in the orbit called when it is the greatest distance from the center of the earth?

A

Apogee

113
Q

What is the angle between the equatorial plane of the earth and the orbital plane of the satellite called?

A

Angle of inclination

114
Q

A satellite orbiting in any plane not identical with the equatorial plane is in which type of orbit?

A

Inclined

115
Q

Which type of orbit is defined by a satellite orbiting in a plane that coincides with the equatorial plane of the earth?

A

Equatorial

116
Q

A satellite in a circular orbit at a height of approximately how many nautical miles above the earth is in a synchronous orbit?

A

19,300

117
Q

A satellite in a circular orbit from approximately 2,000 miles to how many miles above the earth is considered to be in a medium altitude orbit?

A

12,000

118
Q

About how many solar cells mounted on the surface of the satellite do newer communications satellites have?

A

32,000

119
Q

Generally speaking, how many sizes of parabolic-type antennas are currently in use at earth terminal sites?

A

Three

120
Q

Depending on the type used and the operational requirements, transmitters used in earth terminals have output power capabilities that very from 10 watts to how many kilowatts?

A

20

121
Q

Which table provides the coordinates of a satellite or a celestial body at specific times during a given period?

A

Ephemeris

122
Q

What is the period of time called for one earth terminal to yield control to another as a satellite moves out of its area of coverage?

A

Hand over

123
Q

The smallest terminal in the defense communication systems network has effectively an 18-foot antenna and weighs how many pounds?

A

19,500

124
Q

Which year did the Department of the Navy establish the Naval Space Command?

A

1983

125
Q

Which year was the first DSCS Phase III satellite launched into orbit?

A

1984

126
Q

Which publication was written to concisely explain the role of the Navy in the Defense Communications Satellite Program?

A

NTP-2

127
Q

What is the zone called where the satellite can be seen by both the up- and down-link earth terminals?

A

Zone of mutual visibility

ET1 SEP EXAM 2018 (28 decks)

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