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CDC 3D153 > Volume 2 URE > Flashcards

Volume 2 URE Flashcards

1
Q

Equipment used for generating, amplifying, and transmitting RF carrier is collectively called ______________.

A

a transmitter.

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2
Q

What basic receiver function involves having the transmitted electromagnetic wave pass through the receive antenna in such a manner as to induce a voltage in the antenna?

A

Reception

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3
Q

The ability of a receiver to reproduce the signal of a weak station is called ______________.

A

sensitivity.

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4
Q

The ability to reproduce the input signal accurately is the characteristic of the receiver’s ___________.

A

fidelity.

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5
Q 
Which of the following cannot be performed by the receiver's computerized components and microcircuitry?
• Specific equipment fault checks
• Internal equipment tests
• Internal calibrations
• Self-repairs
A

Self-repairs

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6
Q

Resistance of the conductor material in a transmission line results in what type of loss?

A

Copper loss

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7
Q

Leakage loss in a transmission line can be reduced by using a _________.

A

very high-resistance dielectric.

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8
Q

A transmission line that consists of a center conductor placed inside a rigid metal tube functioning as the outer tube is called a ____________.

A

rigid coaxial cable.

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9
Q

Which of the following statements concerning waveguides is false?

  • Very slight damage to the external surface of a waveguide can cause arcing.
  • The conductive material construction is easily dented.
  • Effectiveness of waveguides is hindered by moisture.
  • Waveguides can be destroyed by moisture.
A

Very slight damage to the external surface of a waveguide can cause arcing

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10
Q

What two properties of a transmission line determine its characteristic impedance?

A
  • Inductance

* Capacitance

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11
Q

Using figure 1-10, determine the electrical length if the frequency is changed from 150 MHz to 250 MHz.

A

8.33 wavelengths

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12
Q

Which statement concerning line-lengths is true?

  • Frequency and electrical length are inversely proportional.
  • Frequency and physical length are directly proportional.
  • With constant physical length, frequency and electrical length are directly related.
  • With constant physical length, frequency and electrical length are inversely related.
A

With constant physical length, frequency and electrical length are directly related.

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13
Q

A nonresonant transmission line is a line ___________.

A

having no reflected waves.

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14
Q

If a transmission line is terminated in an open, what will likely result?

A

There would be significant signal loss.

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15
Q

The concept that alternating current changes in magnitude and reverses its direction during each cycle is ______________.

A

what makes radio transmission possible.

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16
Q

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

A

10,000 cycles per second

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17
Q

Which basic field detaches from the antenna and travels through space at great distances?

A

Radiation field

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18
Q

Areas in which no antenna radiation pattern passes through are called ______.

A

nulls.

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19
Q

If the electric field component travels in a plane perpendicular to the Earth’s surface, the radio wave is considered to be polarized __________.

A

vertically.

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20
Q

The actual range of frequencies within the antenna’s bandwidth are called the ____________.

A

frequency range.

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21
Q

What measurement is used to determine whether an antenna is resonant at a particular frequency?

A

Standing wave ratio

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22
Q

The antenna’s ability to both receive and transmit well is known as the antenna’s ___________.

A

reciprocity.

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23
Q

The standard used to measure the antenna’s radiating effectiveness (gain) is the __________.

A

isotropic antenna.

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24
Q

What does the overall effectiveness of an entire transmitting and receiving system depend largely upon?

A

Impedance matching

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25
Q

Which antenna radiates radio energy equally well in all directions?

A

Omni-directional

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26
Q

Which antenna type is usually used on long-range, point-to-point communications where the concentrated radio energy is needed for circuit reliability?

A

Uni-directional

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27
Q

Ungrounded lengths of wire specifically designed to be either a half-wavelength or more than a full wavelength long are called ____________.

A

Hertz antennas.

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28
Q

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

A

Hertz antenna.

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29
Q

What type of directivity does the whip antenna provide?

A

Omni-directional

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30
Q

What is probably the worst antenna that can be used on sky-wave circuits?

A

Whip

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31
Q

What antenna radiates or receives on many of its particular elements?

A

Log-periodic

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32
Q

What is one of the simplest and most functional antennas in use?

A

Half-wave dipole

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33
Q

What is the minimum length for a long-wire antenna?

A

One-half wavelength

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34
Q

A long-wire’s takeoff angle depends on the antenna’s ________.

A

length.

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35
Q

A common satellite antenna is the ___________.

A

parabolic.

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36
Q

A helical satellite antenna radiates with what type of polarization?

A

Circular

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37
Q

Which type of airborne antenna can be designed into any part of an aerospace vehicle’s surface, so that it does not upset its aerodynamic properties?

A

Conformal

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38
Q

In selecting an antenna for a circuit, what is the first thing to consider?

A

Type of propagation

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39
Q

In HF communications, replacing a vertical antenna with a dipole antenna that is a quarter wavelength off the ground, what are you able to get from your antenna transmission?

A

Higher takeoff angle

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40
Q

In siting a radio station, which foliage would have more of an adverse effect on radio wave propagation?

  • Broadleaf trees
  • Evergreen trees
  • Swamp grass
  • Sagebrush
A

Broadleaf trees

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41
Q

What has the greatest effect on an antenna?

a. the Sun
b. the Earth
c. the operator
d. the ionosphere

A

The Earth

42
Q

Which environment would be considered the most difficult for an RF transmissions systems technician to establish and operate a radio from?

a. Amazon
b. North Pole
c. Sahara Desert
d. Sierra Nevada Mountains

A

Amazon

43
Q

Radio sets are left on 24 hours a day in a jungle environment to ___________.

A

prevent short circuits.

44
Q

Which environment type will increase maintenance problems with sand and dust?

A

Desert

45
Q

In a mountainous terrain, with a mountain between you and the distant end, which antenna would be more effective?

a. Whip
b. Dipole
c. Discone
d. Near-vertical incident skywave

A

Near-vertical incident skywave

46
Q

Radio waves that travel near the earth’s surface are called __________.

A

Ground waves

47
Q

The earths conductivity is determined by the _______________.

A

soil and water in the propagation path.

48
Q

Skywave transmission is used for which type of communications?

A

Long distance

49
Q

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

A

angle of incidence.

50
Q

Radio waves angled too low are ___________.

A

absorbed.

51
Q

In HF communication, the lowest frequency that arrives at the distant receiver on 90% of the undisturbed days of the month is called the _____________.

A

lowest usable frequency.

52
Q

Magneton splitting creates two waves called ________.

A

ordinary and extraordinary.

53
Q

In dealing with sky/ground wave propagation, the area of silence where no signals are received is known as the _____________.

A

skip zone.

54
Q

How many regions make up the atmosphere?

A

5

55
Q

Scientists call the ionosphere an extension of the ___________.

A

thermosphere.

56
Q

What happens when high energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere and strike the gas atoms?

A

Ionization

57
Q

Sunspots are disturbances __________.

A

on the sun’s surface.

58
Q

Sunspots occur on an __________.

A

11-year cycle.

59
Q

What US government organization divides the frequency spectrum into different bands?

A

Federal Communications Commission

60
Q

Near-vertical incident skywave operations are most effective when you’re using frequencies in the ____________.

A

lower HF range.

61
Q

What frequency range is most susceptible to jamming?

A

HF

62
Q

What frequency bands does the MILSTAR satellite system use?

A

SHF and EHF

63
Q

VHF and UHF are normally employed in ___________.

A

air-ground communications.

64
Q

What is the primary transmission path for frequencies in the SHF and UHF range?

A

Direct

65
Q

The SHF-EHF range is limited to __________.

A

line-of-sight.

66
Q

The refractive index of air depends on moisture, ____________.

A

atmospheric pressure, and temperature.

67
Q

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

A

Radio, by 15%

68
Q

What permits communication in shadow regions behind obstacles?

A

Diffraction

69
Q

What frequency range will show little effect from precipitation?

A

HF

70
Q

The process in which line of sight radio communications are guided through the air between two layers of the atmosphere is called ___________.

A

ducting.

71
Q

Examples of electronic protection include all of the following except _________.

  • frequency agility
  • communications intelligence
  • electronic and material shielding
  • processes to counter meaconing, interfering, jamming, and intrusion
A

communications intelligence.

72
Q

Which electronic warfare component responds to taskings to search for, intercept, identify, and locate intentional and unintentional sources of radiated energy?

A

Support

73
Q

What is the first step in electronic warfare application?

A

Detection

74
Q

What do we call the process of unscrambling encrypted information so that it becomes intelligible?

A

Decryption

75
Q

How many selectable traffic key slots does the KG-84 have?

A

4

76
Q

Which switch on the KY-57 VINSON zeroizes channels one through five?

A

Fill

77
Q

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

A

over-the-air-rekeying.

78
Q

In frequency hopping operation, the interval for which each transmitter remains on a given frequency is known as __________.

A

hopping rate.

79
Q

From what sources does the RT-1523 SINCGARS radio’s control module obtain instructions during remote and local operations, respectively?

A
  • Remote I/O module

* Front panel

80
Q

Concerning HAVEQUICK II communication multiple word of day (MWOD), how long can each word of day (WOD) be used?

A

24 hours

81
Q

Which statement is not a characteristic of the AN/GRC-171B(V)4 transceiver?
• It operates on frequencies ranging from 116-149.975 MHz
• It provides anti jam communications in AM and FM
• It contains both HAVEQUICK and HAVEQUICK II
• It can communicate on any one of 7,000 channels

A

It operates on frequencies ranging from 116 MHz to 149.975 MHz

82
Q

What is the output power of the AN/GRC-171B(V)4 transceiver?

A

20 W in AM and 50 W in FM

83
Q

What commonly referred to link is the joint tactical information distribution system (JTIDS)?

A

16

84
Q

Which multiple channel access method eliminates the requirement for a net control station in the joint tactical information distribution system (JTIDS)?

A

Time Division

85
Q

What type of network radio does the Air Force use for close air support?

A

Situation Awareness Data Link (SADL)

86
Q

The family of radios that are scaled for use in all domains, will function with programmable waveforms, and be based on a common core architecture is the ________________.

A

joint tactical radio.

87
Q

How many programmable devices can the multi-band inter/intra team radio hold?

A

7

88
Q

Which conventional land mobile radio (LMR) device serves as the hub of a net?

A

Base Station

89
Q

How many talk groups can a trunked mobile radio monitor at one time?

A

1

90
Q

Who has the ability to patch different talk groups together?

A

Dispatch console

91
Q

What Air Force Instruction (AFI) requires communications squadrons to maintain “installation warning systems?”

A

AFI 10-2501

92
Q

What is a common problem with a mass alert system in a deployed environment?

A

Cleanliness

93
Q

In the Whelen siren cabinet, what controls signal routing and power distribution of the system?

A

The motherboard

94
Q

In the Whelen system, how many digits make up the dual tone multi frequency (DTMF) protocol?

A

10

95
Q

In high frequency communications, the station’s self address is the address _____________.

A

which the user programmed into the system.

96
Q

What are the three parts of data of a handshake between calling and receiving stations?

A
  • Call
  • Response
  • Acknowledgement
97
Q

Transmitting a signal on a particular frequency in order to determine that channel’s usability is referred to as _____________.

A

sounding.

98
Q

What is the maximum power of the AN/PRC-150 in FM mode?

A

10 W

99
Q

What assembly in the PRC-150 contains the keyboard and the liquid crystal display (LCD) which make up the man-machine interface?

A

Keyboard Display Unit (KDU)

100
Q

Where do the modulation and digital to analog conversion take place in the AN/PRC-150?

A

Signal Processing and Control Module

CDC 3D153 (5 decks)

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