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1991-08-01
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283 lines
296I-1-3.1 A 7-28 A variation of the cubical quad|but with three sides
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
*
297I-2-1.1 B 7-24 Horizontal polarization refers to the|plane of the electric lines which are|parallel to the horizon
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
*
298I-2-1.2 C 7-27 When fed at top/bottom, it|is Horizontally polarized
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
*
299I-2-1.3 C 7-27 When fed at top/bottom, it|is Horizontally polarized
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
*
300I-2-2.1 D 7-25 Polarization refers to the plane of |the electric lines which is the same|as the antenna orientation
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
*
301I-2-2.2 D 7-25 Mostly vertical
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
*
302I-2-2.3 C 7-24 Vertical polarization refers to the |plane of the electric lines which are|perpendicular to the earth's surface
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
*
303I-2-2.4 D 7-27 When fed at the side it|is Vertically polarized
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
*
304I-2-2.5 D 7-27 When fed at the side it|is Vertically polarized
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
*
305I-3-1.1 D 7-5 SWR refers to the ratio of maximum|to minimum voltages on a feed line
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
*
306I-3-1.2 A 7-5 SWR refers to the ratio of maximum|to minimum voltages on a feed line
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
*
307I-3-2.1 A 7-6 From the transmitter|to the load, which |might be an antenna
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
*
308I-3-2.2 B 7-6 Power reflected by the load back to |the source, like power returned from|an antenna to the transmitter
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
*
309I-3-3.1 D 7-23 As the SWR increases on a feedline|the line losses also increase
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
*
310I-3-3.2 C 7-23 Low-loss lines like open-wire(ladder)|line, are best suited to operation at|a high SWR
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
*
311I-3-3.3 C 7-23 Some is dissipated as heat
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
*
312I-4-1.1 D 7-5 Balanced to ground ie neither|conductor connected to ground
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
*
313I-4-1.2 C 7-5 Coaxial cable is a type of unbalanced|line ie. feed line with one conductor|connected to ground
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
*
314I-4-2.1 B 7-5 Symmetrically fed ie symmetrical|about the feed point, requires a|balanced feed line or a balun
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
*
315I-4-2.2 A 7-5 Not symmetrically fed, ie. one side of|feed is grounded and coaxial cable can|be used without a balun
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
*
316I-4-3.1 A 7-5 BALanced-UNbalanced
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
*
317I-4-3.2 B 7-24 A balun is a device that is installed |on a BALanced antenna so an UNbalanced|feed line like coax can be used
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
*
318I-5-1.1 C 7-24 Open-wire feed line has very little|dielectric losses since most of the|dielectric is air
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
*
319I-5-1.2 A 7-24 Low-loss 50 Ohm coax like RG-8|can be used. There are other|coaxial cables with less loss
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
*
320I-5-2.1 C 7-24 Leave enough to service the equipment |and cut off the rest of the coax cable
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
*
321I-5-2.2 B 7-24 All feed lines have some losses due to|copper resistance and dielectric loss,|as length increases, loss increases
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
*
322I-5-3.1 B 7-24 The copper and dielectric losses of|feed lines tend to increase as the |operating frequency is increased
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
*
323I-5-3.2 A 7-24 The copper and dielectric losses of|feed lines tend to decrease as the |operating frequency is decreased
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
*
324I-5-3.3 B 7-24 The conductor losses of feed lines|tend to increase as the operating|frequency is increased
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
*
325I-6-1.1 D 7-10 RF voltages can be |present and RF burns
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
*
326I-6-2.1 C 7-21 Antennas should be clear of everything|to minimize exposure to RF energy and |to get the best performance from them
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
*