HAM Radio 3/hamradioversion3.0examsandprograms1992.iso/exam/nov20/nov9.dat

Text File | 1991-11-20 | 14KB | 350 lines

336I-1.3   C 7-7   Length for dipole is 468 divided by|F in MHz,  468/21.125 = 22.2 feet
What is the approximate length (in feet) of a half-wavelength
dipole antenna for 21,125 kHz?
A. 44 ft
B. 28 ft
C. 22 ft
D. 14 ft
*
337I-1.4   C 7-7   Length for dipole is 468 divided by|F in MHz,  468/28.150 = 16.6 feet
What is the approximate length (in feet) of a half-wavelength
dipole antenna for 28,150 kHz?
A. 22 ft
B. 11 ft
C. 17 ft
D. 34 ft
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338I-1.5   D 7-7   Length for dipole is 468 divided by|F in MHz
How is the approximate length (in feet) of a half-wavelength
dipole antenna calculated?
A. By substituting the desired operating frequency for f in
   the formula: 150/f (in MHz)
B. By substituting the desired operating frequency for f in
   the formula: 234/f (in MHz)
C. By substituting the desired operating frequency for f in
   the formula: 300/f (in MHz)
D. By substituting the desired operating frequency for f in
   the formula: 468/f (in MHz)
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339I-2.1   D 7-14  The length of a ¼ wavelength vertical|antenna is 234 divided by F in MHz   |234/3.725 = 62.8 feet
What is the approximate length (in feet) of a quarter-wavelength
vertical antenna for 3725 kHz?
A. 20 ft
B. 32 ft
C. 40 ft
D. 63 ft
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340I-2.2   D 7-14  The length of a ¼ wavelength vertical|antenna is 234 divided by F in MHz   |234/7.125 = 32.8 feet
What is the approximate length (in feet) of a quarter-wavelength
vertical antenna for 7125 kHz?
A. 11 ft
B. 16 ft
C. 21 ft
D. 33 ft
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341I-2.3   B 7-14  The length of a ¼ wavelength vertical|antenna is 234 divided by F in MHz   |234/21.125 = 11.1 feet
What is the approximate length (in feet) of a quarter-wavelength
vertical antenna for 21,125 kHz?
A. 7ft
B. 11 ft
C. 14 ft
D. 22 ft
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342I-2.4   B 7-14  The length of a ¼ wavelength vertical|antenna is 234 divided by F in MHz   |234/28.150 = 8.3 feet
What is the approximate length (in feet) of a quarter-wavelength
vertical antenna for 28,150 kHz?
A. 5 ft
B. 8 ft
C. 11 ft
D. 17 ft
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343I-2.5   A 7-14  L = 234/F therefore F = 234/L|Making L, the length, greater|causes F to decrease
When a vertical antenna is lengthened, what happens to its
resonant frequency?
A. It decreases
B. It increases
C. It stays the same
D. It doubles
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344I-3.1   B 7-21  More gain
Why do many amateurs use a 5/8-wavelength vertical antenna
rather than a 1/4-wavelength vertical antenna for their VHF
or UHF mobile stations?
A. A 5/8-wavelength antenna can handle more power than a
   1/4-wavelength antenna
B. A 5/8-wavelength antenna has more gain than a 1/4
   wavelength antenna
C. A 5/8-wavelength antenna exhibits less corona loss than
   a 1/4-wavelength antenna
D. A 5/8-wavelength antenna looks more like a CB antenna,
   so it does not attract as much attention as a 1/4
   wavelength antenna
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345I-3.2   C 7-21  Omni pattern with most |of the radiation going |close to the horizon
What type of radiation pattern is produced by a 5/8-wavelength
vertical antenna?
A. A pattern with most of the transmitted signal concentrated
   in two opposite directions
B. A pattern with the transmitted signal going equally in all
   compass directions, with most of the radiation going high
   above the horizon
C. A pattern with the transmitted signal going equally in all
   compass directions, with most of the radiation going close
   to the horizon
D. A pattern with more of the transmitted signal concentrated
   in one direction than in other directions
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346I.4-1.1 D 7-19  One type of antenna that produces a|directional radiation pattern is a |beam antenna
What type of antenna produces a radiation pattern with more of
the transmitted signal concentrated in a particular direction
than in other directions?
A. A dipole antenna
B. A vertical antenna
C. An isotropic antenna
D. A beam antenna
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347I-4-1.2 B 7-19  Antennas that have a pattern with most|of the power radiated in one direction|are called directional antennas
What type of radiation pattern is produced by a Yagi antenna?
A. A pattern with the transmitted signal spread out equally in
   all compass directions
B. A pattern with more of the transmitted signal concentrated
   in one direction than in other directions
C. A pattern with most of the transmitted signal concentrated
   in two opposite directions
D. A pattern with most of the transmitted signal concentrated
   at high radiation angles
*
348I-4-1.3 C 7-20  Half
Approximately how long (in wavelengths) is the driven element
of a Yagi antenna?
A. 1/4 wavelength
B. 1/3 wavelength
C. 1/2 wavelength
D. 1 wavelength
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349I-4-2.1 D 7-20  The element connected to the feed|line is called the driven element
On the Yagi antenna shown in Figure 2I-4, what is the name of
 section B?
A. Director
B. Reflector
C. Boom
D. Driven element
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350I-4-2.2 A 7-20  The elements that are "in-front" and|are shorter than the driven element |are called directors
On the Yagi antenna shown in Figure 2I-4, what is the name of
 section C?
A. Director
B. Reflector
C. Boom
D. Driven element
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351I-4-2.3 B 7-20  The longest element is the reflector
On the Yagi antenna shown in Figure 2I-4, what is the name of
 section A?
A. Director
B. Reflector
C. Boom
D. Driven element
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352I-4-2.4 A 7-20  Must have driven element and |a director or reflector to be|a Yagi antenna
What are the names of the elements in a 3-element Yagi
antenna?
A. Reflector, driven element and director
B. Boom, mast and reflector
C. Reflector, base and radiator
D. Driven element, trap and feed line
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353I-5.1   A 7-21  Away
How should the antenna on a hand-held transceiver be positioned
while you are transmitting?
A. Away from your head and away from others standing nearby
B. Pointed in the general direction of the repeater or other
   station you are transmitting to
C. Pointed in a general direction 90 degrees away from the
   repeater or other station you are transmitting to
D. With the top of the antenna angled down slightly to take
   the most advantage of ground reflections
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354I-5.2   B 7-21  Antennas work best if away from |all objects and RF tends to burn|or cook people and pets
Why should you always locate your antennas so that no one
can come in contact with them while you are transmitting?
A. Such contact can detune the antenna, causing television
   interference
B. To prevent RF burns and excessive exposure to RF energy
C. The antenna is more likely to radiate harmonics when it
   is touched
D. Such contact may reflect the transmitted signal back to
   the transmitter, damaging the final amplifier
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355I-5.3   C 7-22  Half
You are going to purchase a new antenna for your VHF or UHF
hand-held radio. Which type of antenna is the best choice to
produce a radiation pattern that will be least hazardous to
your face and eyes?
A. A 1/8-wavelength whip
B. A 7/8-wavelength whip
C. A 1/2-wavelength whip
D. A short, helically wound, flexible antenna
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356I-6.1   D 7-2   Two conductors with the same|center (co-axial) usually|separated by an insulator
What is a coaxial cable?
A. Two parallel conductors encased along the edges of a flat
   plastic ribbon
B. Two parallel conductors held at a fixed distance from each
   other by insulating rods
C. Two conductors twisted around each other in a double spiral
D. A center conductor encased in insulating material which is
   covered by a conducting sleeve or shield
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357I-6.2   B 7-2   Coax
What kind of antenna feed line is constructed of a center
conductor encased in insulation which is then covered by an
outer conducting shield and weatherproof jacket?
A. Twin lead
B. Coaxial cable
C. Open-wire feed line
D. Wave guide
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358I-6.3   B 7-2   Impedances are within amateur radio|equipment range and weatherproof
What are some advantages of using coaxial cable as an antenna
feed line?
A. It is easy to make at home, and it has a characteristic
   impedance in the range of most common amateur antennas
B. It is weatherproof, and it has a characteristic impedance
   in the range of most common amateur antennas
C. It can be operated at a higher SWR than twin lead, and it
   is weatherproof
D. It is unaffected by nearby metallic objects, and has a
   characteristic impedance that is higher than twin lead
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359I-6.4   B 7-2   Coax, better inside PVC
What commonly-available antenna feed line can be buried directly
in the ground for some distance without adverse effects?
A. Twin lead
B. Coaxial cable
C. Parallel conductor
D. Twisted pair
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360I-6.5   C 7-2   Coax
When an antenna feed line must be located near grounded metal
objects, which commonly-available feed line should be used?
A. Twisted pair
B. Twin lead
C. Coaxial cable
D. Ladder-line
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361I-7.1   B 7-3   Parallel conductors
What is parallel-conductor feed line?
A. Two conductors twisted around each other in a double spiral
B. Two parallel conductors held a uniform distance apart by
   insulating material
C. A conductor encased in insulating material which is then
   covered by a conducting shield and a weatherproof jacket
D. A metallic pipe whose diameter is equal to or slightly
   greater than the wavelength of the signal being carried
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362I-7.2   C 7-3   Use an impedance-matching network with|a balun and do not run the twin-lead  |close to metal objects
How can TV-type twin lead be used as a feed line?
A. By carefully running the feed line parallel to a metal
   post to ensure self resonance
B. TV-type twin lead cannot be used in an amateur station
C. By installing an impedance-matching network between the
   transmitter and feed line
D. By using a high-power amplifier and installing a power
   attenuator between the transmitter and feed line
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363I-7.3   D 7-3   Lower loss and might operate at|higher SWR than coaxial cable
What are some advantages of using parallel-conductor feed line?
A. It has a lower characteristic impedance than coaxial cable,
   and will operate at a higher SWR than coaxial cable
B. It will operate at a higher SWR than coaxial cable, and it is
   unaffected by nearby metal objects
C. It has a lower characteristic impedance than coaxial cable,
   and has less loss than coaxial cable
D. It will operate at higher SWR than coaxial cable and it has
   less loss than coaxial cable
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364I-7.4   A 7-4   Impedance is usually too high  |and is affected by nearby metal
What are some disadvantages of using parallel-conductor feed line?
A. It is affected by nearby metallic objects, and it has a
   characteristic impedance that is too high for direct connection
   to most amateur transmitters
B. It is more difficult to make at home than coaxial cable and it
   cannot be operated at a high SWR
C. It is affected by nearby metallic objects, and it cannot handle
   the power output of a typical amateur transmitter
D. It has a characteristic impedance that is too high for direct
   connection to most amateur transmitters, and it will operate at
   a high SWR
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365I-7.5   B 7-5   Looks like a ladder
What kind of antenna feed line is constructed of two conductors
maintained a uniform distance apart by insulated spreaders?
A. Coaxial cable
B. Ladder-line open conductor line
C. Twin lead in a plastic ribbon
D. Twisted pair
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366I-8.1   C 7-4   Matching device
A certain antenna has a feed-point impedance of 35 ohms.  You want
to use a 50-ohm-impedance coaxial cable to feed this antenna. What
type of device will you need to connect between the antenna and the
feed line?
A. A balun
B. An SWR bridge
C. An impedance-matching device
D. A low-pass filter
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367I-8.2   C 7-4   Matching device
A certain antenna system has an impedance of 1000 ohms on one
band. What must you use to connect this antenna system to the
50-ohm output on your transmitter?
A. A balun
B. An SWR bridge
C. An impedance-matching device
D. A low-pass filter
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368I-9.1   D 7-5   BALanced-UNbalanced
The word balun is a contraction for what phrase?
A. Balanced-antenna-lobe use network
B. Broadband-amplifier linearly unregulated
C. Balanced unmodulator
D. Balanced to unbalanced
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369I-9.2   A 7-5   Near transmitter
Where would you install a balun if you wanted to feed your
dipole antenna with 450-ohm parallel-conductor feed line?
A. At the transmitter end of the feed line
B. At the antenna feed point
C. ln only one conductor of the feed line
D. From one conductor of the feed line to ground
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370I-9.3   A 7-5   At the antenna feedpoint
Where might you install a balun if you wanted to feed your dipole
antenna with 50-ohm coaxial cable?
A. You might install a balun at the antenna feedpoint
B. You might install a balun at the transmitter output
C. You might install a balun 1/2 wavelength from the transmitter
D. You might install baluns in the middle of each side of the
   dipole
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371I-10-1.1C 7-21  An antenna, like a yagi, that has its |elements parallel to the Horizon, will|produce Horizontal signal polarization
A four-element Yagi antenna is mounted with its elements
parallel to the ground.  A signal produced by this antenna
will have what type of polarization?
A. Broadside polarization
B. Circular polarization
C. Horizontal polarization
D. Vertical polarization
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372I-11-1.1D 7-21  A signal produced by an antenna that|has its elements in a Vertical plane|will be Vertically polarized
A four-element Yagi antenna is mounted with its elements
perpendicular to the ground.  A signal produced by this
antenna will have what type of polarization?
A. Broadside polarization
B. Circular polarization
C. Horizontal polarization
D. Vertical polarization
*