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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
Which antenna radiates radio energy equally well in all directions?
Omni-directional
26
Which antenna type is usually used on long-range, point-to-point communications where the concentrated radio energy is needed for circuit reliability?
Uni-directional
27
Ungrounded lengths of wire specifically designed to be either a half-wavelength or more than a full wavelength long are called ____________.
Hertz antennas.
28
A dipole or long-wire antenna is an example of a _____________.
Hertz antenna.
29
What type of directivity does the whip antenna provide?
Omni-directional
30
What is probably the worst antenna that can be used on sky-wave circuits?
Whip
31
What antenna radiates or receives on many of its particular elements?
Log-periodic
32
What is one of the simplest and most functional antennas in use?
Half-wave dipole
33
What is the minimum length for a long-wire antenna?
One-half wavelength
34
A long-wire's takeoff angle depends on the antenna's ________.
length.
35
A common satellite antenna is the ___________.
parabolic.
36
A helical satellite antenna radiates with what type of polarization?
Circular
37
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?
Conformal
38
In selecting an antenna for a circuit, what is the first thing to consider?
Type of propagation
39
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?
Higher takeoff angle
40
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
Broadleaf trees
41
What has the greatest effect on an antenna? a. the Sun b. the Earth c. the operator d. the ionosphere
The Earth
42
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
Amazon
43
Radio sets are left on 24 hours a day in a jungle environment to ___________.
prevent short circuits.
44
Which environment type will increase maintenance problems with sand and dust?
Desert
45
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
Near-vertical incident skywave
46
Radio waves that travel near the earth's surface are called __________.
Ground waves
47
The earths conductivity is determined by the _______________.
soil and water in the propagation path.
48
Skywave transmission is used for which type of communications?
Long distance
49
The angle at which a radio wave enters the ionosphere is known as the _____________.
angle of incidence.
50
Radio waves angled too low are ___________.
absorbed.
51
In HF communication, the lowest frequency that arrives at the distant receiver on 90% of the undisturbed days of the month is called the _____________.
lowest usable frequency.
52
Magneton splitting creates two waves called ________.
ordinary and extraordinary.
53
In dealing with sky/ground wave propagation, the area of silence where no signals are received is known as the _____________.
skip zone.
54
How many regions make up the atmosphere?
5
55
Scientists call the ionosphere an extension of the ___________.
thermosphere.
56
What happens when high energy ultraviolet light waves from the sun enter the ionospheric region of the atmosphere and strike the gas atoms?
Ionization
57
Sunspots are disturbances __________.
on the sun's surface.
58
Sunspots occur on an __________.
11-year cycle.
59
What US government organization divides the frequency spectrum into different bands?
Federal Communications Commission
60
Near-vertical incident skywave operations are most effective when you're using frequencies in the ____________.
lower HF range.
61
What frequency range is most susceptible to jamming?
HF
62
What frequency bands does the MILSTAR satellite system use?
SHF and EHF
63
VHF and UHF are normally employed in ___________.
air-ground communications.
64
What is the primary transmission path for frequencies in the SHF and UHF range?
Direct
65
The SHF-EHF range is limited to __________.
line-of-sight.
66
The refractive index of air depends on moisture, ____________.
atmospheric pressure, and temperature.
67
When comparing the radio and optical horizons, which one is farther and by what percent?
Radio, by 15%
68
What permits communication in shadow regions behind obstacles?
Diffraction
69
What frequency range will show little effect from precipitation?
HF
70
The process in which line of sight radio communications are guided through the air between two layers of the atmosphere is called ___________.
ducting.
71
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
communications intelligence.
72
Which electronic warfare component responds to taskings to search for, intercept, identify, and locate intentional and unintentional sources of radiated energy?
Support
73
What is the first step in electronic warfare application?
Detection
74
What do we call the process of unscrambling encrypted information so that it becomes intelligible?
Decryption
75
How many selectable traffic key slots does the KG-84 have?
4
76
Which switch on the KY-57 VINSON zeroizes channels one through five?
Fill
77
The common name for the method of changing the encryption keys over the radio channel in a two-way radio system is called __________.
over-the-air-rekeying.
78
In frequency hopping operation, the interval for which each transmitter remains on a given frequency is known as __________.
hopping rate.
79
From what sources does the RT-1523 SINCGARS radio's control module obtain instructions during remote and local operations, respectively?
* Remote I/O module | * Front panel
80
Concerning HAVEQUICK II communication multiple word of day (MWOD), how long can each word of day (WOD) be used?
24 hours
81
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
It operates on frequencies ranging from 116 MHz to 149.975 MHz
82
What is the output power of the AN/GRC-171B(V)4 transceiver?
20 W in AM and 50 W in FM
83
What commonly referred to link is the joint tactical information distribution system (JTIDS)?
16
84
Which multiple channel access method eliminates the requirement for a net control station in the joint tactical information distribution system (JTIDS)?
Time Division
85
What type of network radio does the Air Force use for close air support?
Situation Awareness Data Link (SADL)
86
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 ________________.
joint tactical radio.
87
How many programmable devices can the multi-band inter/intra team radio hold?
7
88
Which conventional land mobile radio (LMR) device serves as the hub of a net?
Base Station
89
How many talk groups can a trunked mobile radio monitor at one time?
1
90
Who has the ability to patch different talk groups together?
Dispatch console
91
What Air Force Instruction (AFI) requires communications squadrons to maintain "installation warning systems?"
AFI 10-2501
92
What is a common problem with a mass alert system in a deployed environment?
Cleanliness
93
In the Whelen siren cabinet, what controls signal routing and power distribution of the system?
The motherboard
94
In the Whelen system, how many digits make up the dual tone multi frequency (DTMF) protocol?
10
95
In high frequency communications, the station's self address is the address _____________.
which the user programmed into the system.
96
What are the three parts of data of a handshake between calling and receiving stations?
* Call * Response * Acknowledgement
97
Transmitting a signal on a particular frequency in order to determine that channel's usability is referred to as _____________.
sounding.
98
What is the maximum power of the AN/PRC-150 in FM mode?
10 W
99
What assembly in the PRC-150 contains the keyboard and the liquid crystal display (LCD) which make up the man-machine interface?
Keyboard Display Unit (KDU)
100
Where do the modulation and digital to analog conversion take place in the AN/PRC-150?
Signal Processing and Control Module

CDC 3D153 (5 decks)

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