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Next Up > M2 B2 > Flashcards

M2 B2 Flashcards

1
Q

Which US government agency divides the radio frequency spectrum into different bands?

A

Federal Communications Commission (FCC)

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2
Q

High-frequency (HF) transmissions are normally conducted in which two operating modes?

A

SSB and ISB

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3
Q

Which frequency band is most susceptible to jamming?

A

High frequency (HF)

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4
Q

The ability of a receiver to reproduce the signal of a very weak station is characteristic of a receiver’s

A

sensitivity

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5
Q

The ability of a receiver to reproduce the input signal accurately is characteristic of its

A

fidelity

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6
Q

A combination transmitter and receiver, built as a single unit and shares common tuned circuits, is called a

A

transceiver

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7
Q

Conductor material resistance in a transmission line leads to this type of loss

A

Copper loss

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8
Q

The amount of skin-effect loss is directly proportional to the

A

frequency

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9
Q

Leakage loss in a transmission line is minimized by using a

A

very high-resistance dielectric

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10
Q

A transmission line that consists of a center conductor, placed inside a rigid metal tube that functions as the outer shield, is called

A

rigid coaxial cable

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11
Q

A waveguide is a type of transmission line that you would use

A

when the frequencies are so high that their wavelength is miniscule

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12
Q

All statements concerning waveguides are true except

A

their outer surface will arc from being very slightly damaged

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13
Q

Which two transmission line properties determine its characteristic impedance (ZO)?

A

Inductance and capacitance

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14
Q

This is the correct statement concerning a wavelength

A

Wavelength is inversely related to frequency.

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15
Q

Determine the wavelength of a 250 megahertz (MHz) signal

A

1.2 meters

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16
Q

A nonresonant transmission line is one with

A

no reflected waves

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17
Q

When discussing resonant and nonresonant transmission lines

A

maximum power transfer results from a nonresonant line

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18
Q

This will likely result if a transmission line is terminated in an open

A

Signal loss would be significant

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19
Q

Direct waves are radio waves that travel

A

through the air in a straight line from transmitter to receiver

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20
Q

Radio waves that travel near the Earth’s surface are called

A

ground waves

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21
Q

The Earth’s conductivity is determined by the type of

A

soil and water in the propagation path

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22
Q

This term is used to describe radio waves that bend as they travel from one medium to another that has different density

A

Refraction

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23
Q

The refractive index of air depends on moisture

A

atmospheric pressure, and temperature

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24
Q

When comparing the radio and optical horizons, which one is farther away and by what percentage?

A

Radio, 15

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25
Q

Which process permits communication in shadow regions behind obstacles?

A

Diffraction

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26
Q

Which frequency range will show little effect from precipitation?

A

High frequency (HF)

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27
Q

Line-of-sight (LOS) radio waves that are guided through the air between two layers of the atmosphere are known as

A

ducting

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28
Q

Which condition gives sky-wave propagation its ability to communicate beyond the optical line-of-sight (LOS)?

A

Refraction

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29
Q

The angle at which a radio wave enters the ionosphere is known as the

A

angle of incidence

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30
Q

There are several critical sky-wave propagation angles and frequencies. Radio waves that angle too low are

A

absorbed before refraction occurs

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31
Q

In sky-wave propagation, frequencies higher than the critical frequency are

A

passed into space

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32
Q

The term frequency of optimum transmission (FOT) is also referred to as the

A

optimum traffic frequency

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33
Q

In sky- and ground-wave propagation, the area of silence where no signals are received is known as the

A

skip zone

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34
Q

This occurs when a transmitted signal travels over two or more separate paths during transmission

A

Multipathing

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35
Q

How many layers make up the Earth’s atmosphere?

A

5

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36
Q

This occurs when high-energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere and strike the gas atoms

A

Ionization

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37
Q

The atmospheric recombination process is dependent on the

A

time of day (TOD)

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38
Q

Which layer of the ionosphere is most important for high-frequency (HF) communications?

A

F

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39
Q

During which season do we have the wider range of critical frequencies and less absorption of all frequencies?

A

Winter

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40
Q

As ionospheric solar variations, sunspots are disturbances that appear and disappear

A

on the sun’s surface

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41
Q

On which regular ionospheric variation do sunspots occur?

A

11-year cycle

42
Q

In a basic communication system, this is used to convert radio frequency (RF) current oscillation into electric and magnetic fields of force.

A

Antenna

43
Q

The concept where alternating current (AC) changes in magnitude, and reverses its direction during each cycle, is

A

what makes radio transmission possible

44
Q

At which point do magnetic fields around a wire no longer have time to collapse completely between alternations?

A

10,000 cps

45
Q

In radio-wave creation, which type of field detaches from the antenna and travels through space at great distances?

A

Radiation

46
Q

Which types of polarization do most satellite communication terminals transmit and receive?

A

Transmit right-hand circular and receive left-hand circular polarizations

47
Q

A resonant antenna effectively radiates a radio signal for frequencies close to its designed frequency. Which percentage range, plus or minus, is it usually within?

A

2

48
Q

The design frequency of a resonant antenna is 10 megahertz (MHz). What will be its frequency range?

A

9.8 - 10.2 MHz

49
Q

The lowest frequency at which an antenna resonates is known as its

A

fundamental

50
Q

The ability of an antenna to both receive and transmit equally well is known as the antenna’s

A

reciprocity

51
Q

This matching device is inserted to make a transmitter “think” it is connected to a low standing-wave ratio (SWR) antenna

A

Coupler

52
Q

This matching device would be used to connect a 52-ohms RG–213 cable to an antenna with an impedance of 600-ohms

A

Balun

53
Q

Which type of antenna radiates radio energy equally well in all directions?

A

Omni-directional

54
Q

Add this device to make a long-wire antenna more directional

A

Terminating resistor

55
Q

Beam width of a directive antenna is measured at the

A

half-power point

56
Q

A dipole or long-wire antenna is an example of a

A

Hertz antenna

57
Q

This is one of the simplest and most functional antennas in use

A

Half-wave dipole

58
Q

The minimum length of a long-wire antenna is

A

one wavelength

59
Q

You should use this type of antenna to communicate over the horizon to an amphibious ship on the move or to a station up to 450 kilometers away

A

Near-vertical incidence sky-wave

60
Q

How are most antennas designed that are used in satellite communications?

A

Directional

61
Q

Which type of polarization is used to radiate a signal using a helical satellite antenna?

A

Cicular

62
Q

This type of antenna is used to transmit and receive microwave signals

A

Horn

63
Q

Where are aircraft antennas normally housed?

A

Inside NONCONDUCTIVE radomes outside or flush with the fuselage.

64
Q

At which vertical angles should the multi-hop, long-distance transmission be used in airborne antenna applications for frequencies in the upper portion of the high-frequency (HF) band?

A

5 and 30 degrees

65
Q

This is the best way to orient line-of-sight (LOS) antennas

A

In a straight path to the receiving station

66
Q

When siting a radio station, which type of foliage would have a more adverse effect on radio-wave propagation?

A

Broadleaf tree

67
Q

This has the greatest effect on an antenna’s radiation pattern

A

Earth

68
Q

This is one fundamental rule about camouflage

A

Straight lines are obvious

69
Q

This is the most effective type of antennas in mountainous terrain that has a mountain between you and the distant end

A

Near-vertical incidence sky-wave

70
Q

Which electronic warfare (EW) component responds to a tasking to search for, intercept, identify, and locate intentional and unintentional sources of radiated energy?

A

Support

71
Q

Electromagnetic (EM) deception, as it applies to electronic warfare (EW), is

A

conveying misleading information to an enemy through the deliberate radiation of EM energy

72
Q

In frequency-hopping (FH) operations, the interval at which each transmitter remains on a given frequency for a specific time is known as

A

dwell time

73
Q

Which type of hopping-rate category changes frequencies approximately 100 times per second?

A

Medium

74
Q

What does the term “ICOM” indicate?

A

Integrated communications security

75
Q

Which statement best identifies the requirements for two transceivers to establish HAVE QUICK (HQ) communications?

A

They must have the same word of day (WOD) and time of day (TOD)

76
Q

How long is each word-of-day (WOD) used with the HAVE QUICK II (HQII) communications multiple word-of-day (MWOD)?

A

24 hours

77
Q

Which tactical data link (TDL) is a secure, full-duplex, point-to-point digital data link that uses satellite, microwave, or terrestrial cable, as opposed to a modulated waveform, to transmit data?

A

Link 11b

78
Q

Which multiple channel access method eliminates the requirement for a net control station (NCS) in the joint tactical information distribution system (JTIDS) by providing node-less communications network architecture?

A

Time division

79
Q

The Air Force integrates with modified close air support aircraft with digitized battlefield information using this type of network.

A

Situation awareness data link (SADL)

80
Q

Which type of advanced waveform was designed to operate on manned, vehicular-based communication systems?

A

Wideband networking

81
Q

Which type of advanced waveform enables data and imagery situational awareness and provides enhanced combat effectiveness?

A

Soldier radio

82
Q

In high-frequency (HF) communications, your station’s automatic link establishment (ALE) self-address is the address

A

the user programmed for his or her station

83
Q

This is the simplest form of an automatic link establishment (ALE) call

A

Individual

84
Q

Which automatic link establishment (ALE) call option lets you call a predefined group of stations with a single shared address, and requires them to respond, one at a time, in a predefined order?

A

Net

85
Q

Where is the primary high frequency global communications system (HFGCS) network control station located?

A

Andrews AFB, Maryland

86
Q

This is not a major network within the Military Auxiliary Radio Service (MARS)

A

Ultra-high frequency (UHF) network

87
Q

The process of unscrambling encrypted information so that it is intelligible is known as

A

Decryption

88
Q

Which type of cryptographic algorithm permits the encryption key to be public?

A

Asymmetric

89
Q

Which secure communications device operates by simply sliding the key tape into the reader?

A

KOI-18

90
Q

The common name for the method of changing encryption keys over the radio channel in a two-way radio system is called

A

over-the-air-rekeying (OTAR)

91
Q

Which type of conventional land mobile radio (LMR) device maximizes the communications distance between lower-powered equipment items?

A

Repeater

92
Q

In a land mobile radio (LMR) repeater system, a device that separates and isolates the incoming receive signal from the outgoing transmit signal and vice versa is known as a

A

duplexer

93
Q

Which type of site configuration was designed to provide coverage for a small geographical area?

A

Single-site

94
Q

This provides the interface between dispatch consoles and the central controller in a typical trunking system

A

Switching equipment

95
Q

When setting up a trunking network, users with common missions or functions are assigned as

A

talkgroups

96
Q

Which statement is not a benefit of having a trunking network?

A

Unbalanced channel loads

97
Q

This differentiates the enterprise land mobile radio (ELMR) network from a regular trunking or conventional network

A

Centralized core controller

98
Q

Which Air Force instruction (AFI) requires communications squadrons to maintain installation notification and warning systems (INWS)?

A

AFI 10–2501, Air Force Emergency Management Program

99
Q

In the giant-voice system, this controls the system’s signal routing and power distribution

A

Control board

100
Q

Which is not a major component of the giant-voice system?

A

Decoder

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