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BICSI RCDD Study Group > Week 30 Chapter 16 Part 1 - Pages 16-1 to 16-37 > Flashcards

Week 30 Chapter 16 Part 1 - Pages 16-1 to 16-37 Flashcards

1
Q

Watts provide an absolute measurement of power

a. True
b. False

A

True

p 16-20

While watts provide an absolute measurement of power, decibels provide a measurement of relative gain or loss of power.

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2
Q

When choosing the antenna support structure for an installation, additional consideration should be given if the structure will be located within the ___ approach area near an airport or heliport (in the United States)

a. 5 km (3 mi)
b. 8 km (5 mi)
c. 10 km (6 mi)
d. 16 km (10 mi)

A

b. 8 km (5 mi)

p 16-31

If in the ≈8 km (5 mi) approach area near an airport or heliport (in the United States)

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3
Q

The ___ of a wireless network is defined by the system’s accessibility, continuity, and consistency of service.

a. Scalability
b. Compatibility
c. Reliability
d. Implementation

A

c. Reliability

p 16-3

The reliability of a wireless network is defined by the system’s accessibility, continuity, and consistency of service

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4
Q

___ is the abrupt change in direction of a wave front at the interface between two dissimilar media such that the incident wave front returns into the medium from which it originated.

a. Reflection
b. Refraction
c. Scattering
d. Diffraction
e. Absorption

A

a. Reflection

p 16-9

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5
Q

___ is the abrupt change in direction of a wave front at the interface between two dissimilar media as the incident wave front enters the second medium.

a. Reflection
b. Refraction
c. Scattering
d. Diffraction
e. Absorption

A

b. Refraction

p 16-9

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6
Q

___ is the change in the level, direction, frequency, or polarization of incident radiation when it encounters small particles or inhomogeneous particles whose size is similar to or smaller than the wavelength of the incident radiation.

a. Reflection
b. Refraction
c. Scattering
d. Diffraction
e. Absorption

A

c. Scattering

p 16-9

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7
Q

___ is the bending of sound, radio, or light waves around an object, barrier, or aperture edge.

a. Reflection
b. Refraction
c. Scattering
d. Diffraction
e. Absorption

A

d. Diffraction

p 16-9

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8
Q

___ is the loss of energy in an electromagnetic signal as it passes through a medium.

a. Reflection
b. Refraction
c. Scattering
d. Diffraction
e. Absorption

A

e. Absorption

p 16-9

At RF frequencies, absorption occurs when gaseous molecules or suspended water particles (e.g., fog) in the atmosphere absorb the signal energy and convert it into heat because of molecular resonance.

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9
Q

___ is the loss incurred by an RF signal due to the natural broadening of the wave front.

a. Dispersion
b. Path loss
c. QoS
d. Fading

A

a. Dispersion

p 16-12

Dispersion is the loss incurred by an RF signal due to the natural broadening of the wave front. The wider the wave front, the less power can be induced into the receiving antenna.

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10
Q

The received power level is inversely proportional to the square of the ___ and directly proportional to the square of the ___.

a. Distance traveled, transmitted signal’s wavelength
b. Transmitted signal’s wavelength, distance traveled

A

a. Distance traveled, transmitted signal’s wavelength

p 16-12

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11
Q

___ is defined as the variation (with time) of the amplitude or relative phase, or both, of one or more of the frequency components of a signal.

a. Dispersion
b. Path loss
c. QoS
d. Fading

A

d. Fading

p 16-12

Fading is defined as the variation (with time) of the amplitude or relative phase, or both, of one or more of the frequency components of a signal.

NOTE: Fading is caused by changes in the characteristics of the propagation path with time.

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12
Q

___ is the propagation phenomenon that results in RF signals reaching the receiving antenna by two or more paths.

a. Multipath fading
b. Delay Spread
c. Direct path
d. Dispersion

A

a. Multipath

p 16-12

The causes of multipath fading include RF signal reflection from natural objects (e.g., mountains) and man-made objects (e.g., buildings).

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13
Q

___ is the result of multiple paths causing reflection, refraction, and scattering of the transmitted signal. Multiple signals are received by the receiver with different amplitudes and delays at different time intervals.

a. Multipath fading
b. Delay Spread
c. Direct path
d. Dispersion

A

b. Delay Spread

p 16-13

Delay spread—The result of multiple paths causing reflection, refraction, and scattering of the transmitted signal. Multiple signals are received by the receiver with different amplitudes and delays at different time intervals.

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14
Q

Heavy moisture in the atmosphere causes disruptions in the transmission of RF signals, mainly above ___.

a. 2.4 GHz
b. 5 GHz
c. 6 GHz
d. 18 GHz

A

c. 6 GHz

p 16.24

Heavy moisture in the atmosphere causes disruptions in the transmission of RF signals, mainly above 6 GHz. This disruption, called rain fade, can be caused by rain, fog, heavy snow, and other moisture related elements.

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15
Q

PTP licensed wireless networks are found in the 6 GHz to 40 GHz ranges and can offer speeds of ___ to ___

a. 10 Mb/s, 1 Gb/s
b. 100 Mb/s, 1 Gb/s
c. 10 Mb/s, 10 Gb/s
d. 100 Mb/s, 10 Gb/s

A

a. 10 Mb/s, 1 Gb/s

p 16-25

PTP licensed wireless networks are found in the 6 GHz to 40 GHz ranges and can offer speeds of 10 Mb/s to 1 Gb/s.

The 6 GHz and 11 GHz frequencies primarily are used for public safety applications, and the 18 GHz and above frequencies are used primarily in the private sector for PTP applications.

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16
Q

For line of sight most PTP radios above ___ GHz require a clear path. Multipoint wireless equipment with frequencies above ___ GHz typically requires LoS.

a. 2, 5
b. 1, 5
c. 2, 4
d. 1, 2

A

d. 1, 2

p 16-26

17
Q

RF equipment under IEEE 802.11 can penetrate walls and other materials at short distances and are considered non-LoS RF.

a. True
b. False

A

False

p 16-26

Indoor RF equipment falling under IEEE 802.11 can penetrate walls and other materials at short distances, but they are not considered non-LoS RF. The lower ranges of the spectrum, below 2 GHz, are the most common for non-LoS applications.

18
Q

Path loss of ___ dB isotropic is common when using radomes.

a. 0.5
b. 1
c. 3
d. 6

A

a. 0.5

p 16-27

These covers, however, cause some loss in the RF signal as it passes through the cover. This loss should be accounted for in the path loss calculation. Path loss of 0.5 dB isotropic is common when using radomes

19
Q

Time division duplex can transmits and receives both analog and digital RF alternately in sequential time slots on a single frequency.

a. True
b. False

A

False - digital only

p 16-28

Transmits and receives at RF alternately in sequential time slots on a single frequency. Because of buffering of the baseband signal, the baseband interface is full-duplex. Digital only. Found in selected digital cordless telephone systems, telemetry, WLAN, and data links.

20
Q

Frequency division duplex transmits and receives simultaneously with transmitter and receiver operating on ___ pair of frequency(ies) or duplex channel assigned in accordance with a band plan.

a. Same
b. Separate

A

b. Separate

p 16-28

Applies to both analog and digital systems. Used for repeaters, PTP links, duplex, two-way radio, and cellular telephone systems. This is also called full-duplex.

21
Q

Tower lighting is required when working more than ___ in height or within the 5 mi (≈8 km) jurisdiction of an airport or heliport (this will be determined when filing a construction permit with the local aviation authority).

a. 50 ft
b. 100 ft
c. 150 ft
d. 200 ft

A

d. 200 ft

p 16-32

22
Q

When electronic equipment turns ac to dc, it draws current in ___.

a. Harmonics
b. Noise
c. Phases
d. Pulses

A

d. Pulses

p 16-19

When electronic equipment turns ac to dc, it draws current in pulses. These pulses can cause distorted current wave shapes that are rich in harmonics of the fundamental frequency (see Figure 16.10).

23
Q

___ used as a transmission line to feed radio frequency (RF) power contains balanced currents in its two conductors, resulting in no net external field.

a. Coaxial cabling
b. Open wire

A

b. Open wire

p 16-29

Open wire or balanced lines generally comprise parallel unshielded conductors fed and terminated in a balanced manner with respect to Earth. In principle, the current in one conductor exactly balances that in the other conductor resulting in no net external field.

24
Q

The frequencies from ___ are most prevalent in the wireless deployments for the unlicensed spectrum.

a. 12 GHz to 18 GHz
b. 6 GHz to 11 GHz
c. 2.4 GHz to 5 GHz
d. 900 MHz to 3 GHz

A

c. 2.4 GHz to 5 GHz

p 16-25

Although the spectrum range below 2.4 GHz has unlicensed space available, these frequencies are used primarily by amateur radio operators, 900 MHz wireless Internet SPs, and SCADA communications.

25
Q

___ is the standard modulation technique for 802.11a/g/n/ac wireless local area networks (WLANs).

a. Complementary code keying (CCK)
b. Binary phase shift keying (BPSK)
c. Quadrature amplitude modulation (QAM)
d. Orthogonal frequency division multiplexing (OFDM)

A

d. Orthogonal frequency division multiplexing (OFDM)

p 16-18

OFDM has been adopted as the standard modulation technique for 802.11a, g, n, ac, 802.22, European digital TV standards, and 4G cellular.

It is inherently insensitive to multipath distortion and can be quickly scaled up or down in bandwidth by adding or subtracting the quantity of subcarriers.

26
Q

Intermodulation interference occurs when two or more strong signals pass through a _____ device and multiply by each other.

a. Linear
b. Nonlinear

A

b. Nonlinear

p 16-20

Antennas in close proximity can cause intermodulation that will interfere with other systems. Intermodulation distortion occurs when two or more strong signals pass
through a nonlinear device and multiply by each other.

27
Q

A radio frequency line of sight (RF LoS) _____ a visual line of sight (LoS).

a. Always has
b. May not include

A

b. May not include

p 16-7

RF LoS—LoS between the receiving and transmitting antennas. There may not be a visual LoS, but there are no modifications to the EM waves being propagated with the LoS Fresnel zone.

28
Q

With radio frequency line of sight (RF LoS) propagation, there may be modifications to the electromagnetic waves being propagated.

a. True
b. False

A

b. False

p 16-7

RF LoS—LoS between the receiving and transmitting antennas. There may not be a visual LoS, but there are no modifications to the EM waves being propagated with the LoS Fresnel zone.

29
Q

Midspan powering requires that the equipment will be powered over the _____ the balanced twisted-pair cable.

a. Same wire pairs that are used for data transmission over
b. Unused pairs of

A

b. Unused pairs of

p 16-36

IEEE 802.3af states two powering methods in use:
• Midspan requires that the equipment will be powered over the unused pairs of the balanced twisted-pair cable.
• Endspan will run the power over the same wire pairs that are used for data transmission.

30
Q

_____ is the process of altering the amplitude, frequency, or phase of a carrier signal in a measured way, which allows for other signals such as voice, data, and video to be added to it.

a. Sampling
b. Conversion
c. Multiplexing
d. Modulation

A

d. Modulation

p 16-14

Modulation is the process of altering the amplitude, frequency, or phase of a carrier signal in a m

31
Q

In wireless transmission, multi-path fading results in RF signals reaching the receiving antenna by two or more paths. One possible outcome of multi-path fading is an
increase of signal strength, which is known as:

a. Upfade
b. Downfade
c. Nulling
d. Data corruption

A

a. Upfade

p 16-13

The possible outcomes of multipath are:
• Intersymbol interference, known as data corruption.
• A cancellation of signal, known as nulling.
• A decrease of signal strength, known as downfade.
• An increase of signal strength, known as upfade.

32
Q

In wireless transmission, _____ division duplex transceivers are also referred to as full-duplex devices, capable of simultaneous transmission and reception.

a. Phase
b. Pulse
c. Time
d. Frequency

A

d. Frequency

p 16-28 Table 16.2

Used for repeaters, PTP links, duplex, two-way radio, and cellular telephone systems. This is also called full-duplex.

33
Q

You are working with the local city hall to develop a public safety wireless network that will be secured from interference and have the capability of delivering up 10 Mbps subscriber speed. What microwave frequency should be used to best meet these needs?

a. 2.4 Ghz
b. 4.9 Ghz
c. 5.0 Ghz
d. 5.3 Ghz

A

c. 5.0 Ghz

p 16-25

BICSI RCDD Study Group (34 decks)

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