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1992-01-26
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FCC TECHNICIAN Exam Question Pool. Subelement 3AI.
Antennas and Feedlines. 3 Questions.
---------------------------------------------------
3AI 1-1.1 A
What antenna type best strengthens signals from a particular
direction while attenuating those from other directions?
A. A beam antenna
B. An isotropic antenna
C. A monopole antenna
D. A vertical antenna
3AI 1-1.2 D
What is a directional antenna?
A. An antenna whose parasitic elements are all constructed to
be directors
B. An antenna that radiates in direct line-of-sight propagation,
but not sky-wave or skip propagation
C. An antenna permanently mounted so as to radiate in only one
direction
D. An antenna that radiates more strongly in some directions
than others
3AI 1-1.3 C
What is a Yagi antenna?
A. Half-wavelength elements stacked vertically and excited in
phase
B. Quarter-wavelength elements arranged horizontally and
excited out of phase
C. Half-wavelength linear driven element(s) with parasitically
excited parallel linear elements
D. Quarter-wavelength, triangular loop elements
3AI 1-1.4 A
What is the general configuration of the radiating elements
of a horizontally polarized Yagi?
A. Two or more straight, parallel elements arranged in the
same horizontal plane
B. Vertically stacked square or circular loops arranged in
parallel horizontal planes
C. Two or more wire loops arranged in parallel vertical
planes
D. A vertical radiator arranged in the center of an effective
RF ground plane
3AI 1-1.5 C
What type of parasitic beam antenna uses two or more straight
metal-tubing elements arranged physically parallel to each
other?
A. A delta loop antenna
B. A quad antenna
C. A Yagi antenna
D. A Zepp antenna
3AI 1-1.6 B
How many directly driven elements does a Yagi antenna
have?
A. None; they are all parasitic
B. One
C. Two
D. All elements are directly driven
3AI 1-1.7 A
What is a parasitic beam antenna?
A. An antenna where the director and reflector elements
receive their RF excitation by induction or radiation
from the driven element
B. An antenna where wave traps are used to assure magnetic
coupling among the elements
C. An antenna where all elements are driven by direct
connection to the feed line
D. An antenna where the driven element receives its RF
excitation by induction or radiation from the directors
3AI 1-2.1 B
What is a cubical quad antenna?
A. Four parallel metal tubes, each approximately 1/2 electrical
wavelength long
B. Two or more parallel four-sided wire loops, each approximately
one electrical wavelength long
C. A vertical conductor 1/4 electrical wavelength high, fed at
the bottom
D. A center-fed wire 1/2 electrical wavelength long
3AI 1-2.2 B
What kind of antenna array is composed of a square full-wave
closed loop driven element with parallel parasitic element(s)?
A. Delta loop
B. Cubical quad
C. Dual rhombic
D. Stacked Yagi
3AI 1-2.3 D
Approximately how long is one side of the driven element of
a cubical quad antenna?
A. 2 electrical wavelengths
B. 1 electrical wavelength
C. 1/2 electrical wavelength
D. 1/4 electrical wavelength
3AI 1-2.4 C
Approximately how long is the wire in the driven element of
a cubical quad antenna?
A. 1/4 electrical wavelength
B. 1/2 electrical wavelength
C. 1 electrical wavelength
D. 2 electrical wavelengths
3AI 1-3.1 A
What is a delta loop antenna?
A. A variation of the cubical quad antenna, with triangular
elements
B. A large copper ring, used in direction finding
C. An antenna system composed of three vertical antennas,
arranged in a triangular shape
D. An antenna made from several coils of wire on an insulating
form
3AI 2-1.1 B
To what does the term horizontal as applied to wave
polarization refer?
A. The magnetic lines of force in the radio wave are
parallel to the earth's surface
B. The electric line of force in the radio wave are
parallel to the earth's surface
C. The electric line of force in the radio wave are
perpendicular to the earth's surface
D. The radio wave will leave the antenna and radiate
horizontally to the destination
3AI 2-1.2 C
What electromagnetic wave polarization does a cubical
quad antenna have when the feed point is in the center
of a horizontal side?
A. Circular
B. Helical
C. Horizontal
D. Vertical
3AI 2-1.3 C
What electromagnetic wave polarization does a cubical quad
antenna have when all sides are at 45 degrees to the earth's
surface and the feed point is at the bottom corner?
A. Circular
B. Helical
C. Horizontal
D. Vertical
3AI 2-2.1 D
What is the polarization of electromagnetic waves radiated from
a half-wavelength antenna perpendicular to the earth's surface?
A. Circularly polarized waves
B. Horizontally polarized waves
C. Parabolically polarized waves
D. Vertically polarized waves
3AI 2-2.2 D
What is the electromagnetic wave polarization of most man-made
electrical noise radiation in the HF-VHF spectrum?
A. Horizontal
B. Left-hand circular
C. Right-hand circular
D. Vertical
3AI 2-2.3 C
To what does the term vertical as applied to wave
polarization refer?
A. The electric lines of force in the radio wave are
parallel to the earth's surface
B. The magnetic lines of force in the radio wave are
perpendicular to the earth's surface
C. The electric lines of force in the radio wave are
perpendicular to the earth's surface
D. The radio wave will leave the antenna and radiate
vertically into the ionosphere
3AI 2-2.4 D
What electromagnetic wave polarization does a cubical
quad antenna have when the feed point is in the center
of a vertical side?
A. Circular
B. Helical
C. Horizontal
D. Vertical
3AI 2-2.5 D
What electromagnetic wave polarization does a cubical quad
antenna have when all sides are at 45 degrees to the earth's
surface and the feed point is at a side corner?
A. Circular
B. Helical
C. Horizontal
D. Vertical
3AI 3-1.1 D
What is meant by the term standing wave ratio?
A. The ratio of maximum to minimum inductances on a feed line
B. The ratio of maximum to minimum resistances on a feed line
C. The ratio of maximum to minimum impedances on a feed line
D. The ratio of maximum to minimum voltages on a feed line
3AI 3-1.2 A
What is standing wave ratio a measure of?
A. The ratio of maximum to minimum voltage on a feed line
B. The ratio of maximum to minimum reactance on a feed line
C. The ratio of maximum to minimum resistance on a feed line
D. The ratio of maximum to minimum sidebands on a feed line
3AI 3-2.1 A
What is meant by the term forward power?
A. The power traveling from the transmitter to the antenna
B. The power radiated from the front of a directional antenna
C. The power produced during the positive half of the RF cycle
D. The power used to drive a linear amplifier
3AI 3-2.2 B
What is meant by the term reflected power?
A. The power radiated from the back of a directional antenna
B. The power returned to the transmitter from the antenna
C. The power produced during the negative half of the RF cycle
D. Power reflected to the transmitter site by buildings and trees
3AI 3-3.1 D
What happens to the power loss in an unbalanced feed line
as the standing wave ratio increases?
A. It is unpredictable
B. It becomes nonexistent
C. It decreases
D. It increases
3AI 3-3.2 C
What type of feed line is best suited to operating at a
high standing wave ratio?
A. Coaxial cable
B. Flat ribbon "twin lead"
C. Parallel open-wire line
D. Twisted pair
3AI 3-3.3 C
What happens to RF energy not delivered to the antenna by
a lossy coaxial cable?
A. It is radiated by the feed line
B. It is returned to the transmitter's chassis ground
C. Some of it is dissipated as heat in the conductors and
dielectric
D. It is canceled because of the voltage ratio of forward
power to reflected power in the feed line
3AI 4-1.1 D
What is a balanced line?
A. Feed line with one conductor connected to ground
B. Feed line with both conductors connected to ground
to balance out harmonics
C. Feed line with the outer conductor connected to
ground at even intervals
D. Feed line with neither conductor connected to ground
3AI 4-1.2 C
What is an unbalanced line?
A. Feed line with neither conductor connected to ground
B. Feed line with both conductors connected to ground to
suppress harmonics
C. Feed line with one conductor connected to ground
D. Feed line with the outer conductor connected to ground
at uneven intervals
3AI 4-2.1 B
What is a balanced antenna?
A. A symmetrical antenna with one side of the feed point
connected to ground
B. An antenna (or a driven element in an array) that is
symmetrical about the feed point
C. A symmetrical antenna with both sides of the feed point
connected to ground, to balance out harmonics
D. An antenna designed to be mounted in the center
3AI 4-2.2 A
What is an unbalanced antenna?
A. An antenna (or a driven element in an array) that is
not symmetrical about the feed point
B. A symmetrical antenna, having neither half connected
to ground
C. An antenna (or a driven element in an array) that is
symmetrical about the feed point
D. A symmetrical antenna with both halves coupled to
ground at uneven intervals
3AI 4-3.1 A
What device can be installed on a balanced antenna so that it
can be fed through a coaxial cable?
A. A balun
B. A loading coil
C. A triaxial transformer
D. A wavetrap
3AI 4-3.2 B
What is a balun?
A. A device that can be used to convert an antenna designed
to be fed at the center so that it may be fed at one end
B. A device that may be installed on a balanced antenna so
that it may be fed with unbalanced feed line
C. A device that can be installed on an antenna to produce
horizontally polarized or vertically polarized waves
D. A device used to allow an antenna to operate on more than
one band
3AI 5-1.1 C
List the following types of feed line in order of increasing
attenuation per 100 feet of line (list the line with the lowest
attenuation first): RG-8, RG-58, RG-174 and open-wire line.
A. RG-174, RG-58, RG-8, open-wire line
B. RG-8, open-wire line, RG-58, RG-174
C. open-wire line, RG-8, RG-58, RG-174
D. open-wire line, RG-174, RG-58, RG-8
3AI 5-1.2 A
You have installed a tower 150 feet from your radio shack, and
have a 6-meter Yagi antenna on top. Which of the following feed
lines should you choose to feed this antenna: RG-8, RG-58, RG-59
or RG-174?
A. RG-8
B. RG-58
C. RG-59
D. RG-174
3AI 5-2.1 C
You have a 200-foot coil of RG-58 coaxial cable attached
to your antenna, but the antenna is only 50 feet from
your radio. To minimize feed-line loss, what should you
do with the excess cable?
A. Cut off the excess cable to an even number of wavelengths
long
B. Cut off the excess cable to an odd number of wavelengths
long
C. Cut off the excess cable
D. Roll the excess cable into a coil a tenth of a wavelength
in diameter
3AI 5-2.2 B
How does feed-line length affect signal loss?
A. The length has no effect on signal loss
B. As length increases, signal loss increases
C. As length decreases, signal loss increases
D. The length is inversely proportional to signal loss
3AI 5-3.1 B
What is the general relationship between frequencies passing
through a feed line and the losses in the feed line?
A. Loss is independent of frequency
B. Loss increases with increasing frequency
C. Loss decreases with increasing frequency
D. There is no predictable relationship
3AI 5-3.2 A
As the operating frequency decreases, what happens to conductor
losses in a feed line?
A. The losses decrease
B. The losses increase
C. The losses remain the same
D. The losses become infinite
3AI 5-3.3 B
As the operating frequency increases, what happens to conductor
losses in a feed line?
A. The losses decrease
B. The losses increase
C. The losses remain the same
D. The losses decrease to zero
3AI 6-1.1 D
You are using open-wire feed line in your Amateur Radio station.
Why should you ensure that no one can come in contact with the
feed line while you are transmitting?
A. Because contact with the feed line while transmitting will
cause a short circuit, probably damaging your transmitter
B. Because the wire is so small they may break it
C. Because contact with the feed line while transmitting will
cause parasitic radiation
D. Because high RF voltages can be present on open-wire feed
line
3AI 6-2.1 C
How can you minimize exposure to radio frequency energy
from your transmitting antennas?
A. Use vertical polarization
B. Use horizontal polarization
C. Mount the antennas where no one can come near them
D. Mount the antenna close to the ground
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End of Subelement 3AI.