G9A02
What is the typical characteristic impedance of coaxial cables used for
antenna feedlines at amateur stations?
A. 25 and 30 ohms
B. 50 and 75 ohms
C. 80 and 100 ohms
D. 500 and 750 ohms
G9A03
What is the characteristic impedance of flat ribbon TV type twin lead?
A. 50 ohms
B. 75 ohms
C. 100 ohms
D. 300 ohms
G9A04
What is a common reason for the occurrence of reflected power at
the point where a feedline connects to an antenna?
A. Operating an antenna at its resonant frequency
B. Using more transmitter power than the antenna can handle
C. A difference between feedline impedance and antenna feed point impedance
D. Feeding the antenna with unbalanced feedline
G9A05
What must be done to prevent standing waves on an antenna feedline?
A. The antenna feed point must be at DC ground potential
B. The feedline must be cut to an odd number of electrical quarter wavelengths long
C. The feedline must be cut to an even number of physical half
wavelengths long
D. The antenna feed point impedance must be matched to the characteristic impedance
of the feedline
G9A06
Which of the following is a reason for using an inductively coupled matching
network between the transmitter and parallel conductor feed line feeding an antenna?
A. To increase the radiation resistance
B. To reduce spurious emissions
C. To match the unbalanced transmitter output to the balanced parallel conductor
feedline
D. To reduce the feed-point impedance of the antenna
G9A07
How does the attenuation of coaxial cable change as the frequency of
the signal it is carrying increases?
A. It is independent of frequency
B. It increases
C. It decreases
D. It reaches a maximum at approximately 18 MHz
G9A08
In what values are RF feed line losses usually expressed?
A. ohms per 1000 ft
B. dB per 1000 ft
C. ohms per 100 ft
D. dB per 100 ft
G9A09
What standing-wave-ratio will result from the connection of a 50-ohm
feed line to a non-reactive load having a 200-ohm impedance?
A. 4:1
B. 1:4
C. 2:1
D. 1:2
G9A10
What standing-wave-ratio will result from the connection of a 50-ohm
feed line to a non-reactive load having a 10-ohm impedance?
A. 2:1
B. 50:1
C. 1:5
D. 5:1
G9A11
What standing-wave-ratio will result from the connection of a 50-ohm
feed line to a non-reactive load having a 50-ohm impedance?
A. 2:1
B. 1:1
C. 50:50
D. 0:0
G9A12
What would be the SWR if you feed a vertical antenna that has a 25-ohm
feed-point impedance with 50-ohm coaxial cable?
A. 2:1
B. 2.5:1
C. 1.25:1
D. You cannot determine SWR from impedance values
G9A13
What would be the SWR if you feed a folded dipole antenna that has a 300-ohm
feed-point impedance with 50-ohm coaxial cable?
A. 1.5:1
B. 3:1
C. 6:1
D. You cannot determine SWR from impedance values
G9A14
If the SWR on an antenna feedline is 5 to 1, and a matching network at
the transmitter end of the feedline is adjusted to 1 to 1 SWR, what is
the resulting SWR on the feedline?
A. 1 to 1
B. 5 to 1
C. Between 1 to 1 and 5 to 1 depending on the characteristic impedance of the line
D. Between 1 to 1 and 5 to 1 depending on the reflected power at the transmitter
G9B02
What is an advantage of downward sloping radials on a ground-plane antenna?
A. They lower the radiation angle
B. They bring the feed-point impedance closer to 300 ohms
C. They increase the radiation angle
D. They can be adjusted to bring the feed-point impedance closer to 50 ohms
G9B03
What happens to the feed-point impedance of a ground-plane antenna when
its radials are changed from horizontal to downward-sloping?
A. It decreases
B. It increases
C. It stays the same
D. It reaches a maximum at an angle of 45 degrees
G9B04
What is the low angle azimuthal radiation pattern of an ideal half-wavelength
dipole antenna installed 1/2 wavelength high and parallel to the earth?
A. It is a figure-eight at right angles to the antenna
B. It is a figure-eight off both ends of the antenna
C. It is a circle (equal radiation in all directions)
D. It has a pair of lobes on one side of the antenna and a single lobe on the other
side
G9B05
How does antenna height affect the horizontal (azimuthal) radiation pattern of a
horizontal dipole HF antenna?
A. If the antenna is too high, the pattern becomes unpredictable
B. Antenna height has no effect on the pattern
C. If the antenna is less than 1/2 wavelength high, the azimuthal
pattern is almost omnidirectional
D. If the antenna is less than 1/2 wavelength high, radiation off the ends of the
wire is eliminated
G9B06
Where should the radial wires of a ground-mounted vertical antenna system be placed?
A. As high as possible above the ground
B. Parallel to the antenna element
C. On the surface or buried a few inches below the ground
D. At the top of the antenna
G9B07
How does the feed-point impedance of a 1/2 wave dipole antenna change as the
antenna is lowered from 1/4 wave above ground?
A. It steadily increases
B. It steadily decreases
C. It peaks at about 1/8 wavelength above ground
D. It is unaffected by the height above ground
G9B08 (A)
How does the feed-point impedance of a 1/2 wave dipole change as the
feed-point location is moved from the center toward the ends?
A. It steadily increases
B. It steadily decreases
C. It peaks at about 1/8 wavelength from the end
D. It is unaffected by the location of the feed-point
G9B09 (A)
Which of the following is an advantage of a horizontally polarized as
compared to vertically polarized HF antenna?
A. Lower ground reflection losses
B. Lower feed-point impedance
C. Shorter Radials
D. Lower radiation resistance
G9B10
What is the approximate length for a 1/2-wave dipole antenna cut for 14.250 MHz?
A. 8.2 feet
B. 16.4 feet
C. 24.6 feet
D. 32.8 feet
G9B11
What is the approximate length for a 1/2-wave dipole antenna cut for 3.550 MHz?
A. 42.2 feet
B. 84.5 feet
C. 131.8 feet
D. 263.6 feet
G9B12
What is the approximate length for a 1/4-wave vertical antenna
cut for 28.5 MHz?
A. 8.2 feet
B. 10.5 feet
C. 16.4 feet
D. 21.0 feet
G9C02
What is the approximate length of the driven element of a Yagi antenna?
A. 1/4 wavelength
B. 1/2 wavelength
C. 3/4 wavelength
D. 1 wavelength
G9C03
Which statement about a three-element single-band Yagi antenna is true?
A. The reflector is normally the shortest parasitic element
B. The director is normally the shortest parasitic element
C. The driven element is the longest parasitic element
D. Low feed-point impedance increases bandwidth
G9C04
Which statement about a Yagi antenna is true?
A. The reflector is normally the longest parasitic element
B. The director is normally the longest parasitic element
C. The reflector is normally the shortest parasitic element
D. All of the elements must be the same length
G9C05
What is one effect of increasing the boom length and adding directors
to a Yagi antenna?
A. Gain increases
B. SWR increases
C. Weight decreases
D. Wind load decreases
G9C06
Which of the following is a reason why a Yagi antenna is often used for
radio communications on the 20 meter band?
A. It provides excellent omnidirectional coverage in the horizontal plane
B. It is smaller, less expensive and easier to erect than a dipole or
vertical antenna
C. It helps reduce interference from other stations to the side or
behind the antenna
D. It provides the highest possible angle of radiation for the HF bands
G9C07
What does "front-to-back ratio" mean in reference to a Yagi antenna?
A. The number of directors versus the number of reflectors
B. The relative position of the driven element with respect to the
reflectors and directors
C. The power radiated in the major radiation lobe compared to the power
radiated in exactly the opposite direction
D. The ratio of forward gain to dipole gain
G9C08
What is meant by the "main lobe" of a directive antenna?
A. The magnitude of the maximum vertical angle of radiation
B. The point of maximum current in a radiating antenna element
C. The maximum voltage standing wave point on a radiating element
D. The direction of maximum radiated field strength from the antenna
G9C09
What is the approximate maximum theoretical forward gain
of a 3 Element Yagi antenna?
A. 9.7 dBi
B. 7.3 dBd
C. 5.4 times the gain of a dipole
D. All of these choices are correct
G9C10
Which of the following is a Yagi antenna design variable that could be
adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth?
A. The physical length of the boom
B. The number of elements on the boom
C. The spacing of each element along the boom
D. All of these choices are correct
G9C11
What is the purpose of a "gamma match" used with Yagi antennas?
A. To match the relatively low feed-point impedance to 50 ohms
B. To match the relatively high feed-point impedance to 50 ohms
C. To increase the front to back ratio
D. To increase the main lobe gain
G9C12
Which of the following describes a common method for insulating the driven
element of a Yagi antenna from the metal boom when using a gamma match?
A. Support the driven element with ceramic standoff insulators
B. Insert a high impedance transformer at the driven element
C. Insert a high voltage balun at the driven element
D. None of these answers are correct. No insulation is needed
G9C13
Approximately how long is each side of a cubical-quad antenna driven element?
A. 1/4 wavelength
B. 1/2 wavelength
C. 3/4 wavelength
D. 1 wavelength
G9C14
How does the forward gain of a 2-element cubical-quad antenna compare to the
forward gain of a 3 element Yagi antenna?
A. 2/3
B. About the same
C. 3/2
D. Twice
G9C15
Approximately how long is each side of a cubical-quad antenna reflector
element?
A. Slightly less than 1/4 wavelength
B. Slightly more than 1/4 wavelength
C. Slightly less than 1/2 wavelength
D. Slightly more than 1/2 wavelength
G9C16
How does the gain of a two element delta-loop beam compare to the gain of a
two element cubical quad antenna?
A. 3 dB higher
B. 3 dB lower
C. 2.54 dB higher
D. About the same
G9C17
Approximately how long is each leg of a symmetrical delta-loop antenna
Driven element?
A. 1/4 wavelengths
B. 1/3 wavelengths
C. 1/2 wavelengths
D. 2/3 wavelengths
G9C18
Which of the following antenna types consists of a driven element and some
combination of parasitically excited reflector and/or director elements?
A. A collinear array
B. A rhombic antenna
C. A double-extended Zepp antenna
D. A Yagi antenna
G9C19
What type of directional antenna is typically constructed from 2 square
loops of wire each having a circumference of approximately one wavelength at
the operating frequency and separated by approximately 0.2 wavelength?
A. A stacked dipole array
B. A collinear array
C. A cubical quad antenna
D. An Adcock array
G9C20 (A)
What happens when the feed-point of a cubical quad antenna is changed from the
center of the lowest horizontal wire to the center of one of the vertical wires?
A. The polarization of the radiated signal changes from horizontal to vertical
B. The polarization of the radiated signal changes from vertical to horizontal
C. The direction of the main lobe is reversed
D. The radiated signal changes to an omnidirectional pattern
G9C21 (D)
What configuration of the loops of a cubical-quad antenna must be used for
the antenna to operate as a beam antenna, assuming one of the elements is
used as a reflector?
A. The driven element must be fed with a balun transformer
B. The driven element must be open-circuited on the side opposite the feed-point
C. The reflector element must be approximately 5% shorter than the driven element
D. The reflector element must be approximately 5% longer than the driven element
G9D02
Which of the following is an advantage of an NVIS antenna?
A. Low vertical angle radiation for DX work
B. High vertical angle radiation for short skip during the day
C. High forward gain
D. All of these choices are correct
G9D03
At what height above ground is an NVIS antenna typically installed?
A. As close to one-half wave as possible
B. As close to one wavelength as possible
C. Height is not critical as long as significantly more than 1/2 wavelength
D. Between 1/10 and 1/4 wavelength
G9D04
How does the gain of two 3-element horizontally polarized Yagi antennas
spaced vertically 1/2 wave apart from each other typically compare to the
gain of a single 3-element Yagi?
A. Approximately 1.5 dB higher
B. Approximately 3 dB higher
C. Approximately 6 dB higher
D. Approximately 9 dB higher
G9D05
What is the advantage of vertical stacking of horizontally polarized Yagi antennas?
A. Allows quick selection of vertical or horizontal polarization
B. Allows simultaneous vertical and horizontal polarization
C. Narrows the main lobe in azimuth
D. Narrows the main lobe in elevation
G9D06
Which of the following is an advantage of a log periodic antenna?
A. Wide bandwidth
B. Higher gain per element than a Yagi antenna
C. Harmonic suppression
D. Polarization diversity
G9D07
Which of the following describes a log periodic antenna?
A. Length and spacing of the elements increases logarithmically from one end of
the boom to the other
B. Impedance varies periodically as a function of frequency
C. Gain varies logarithmically as a function of frequency
D. SWR varies periodically as a function of boom length
G9D08
Why is a Beverage antenna generally not used for transmitting?
A. Its impedance is too low for effective matching
B. It has high losses compared to other types of antennas
C. It has poor directivity
D. All of these choices are correct
G9D09
Which of the following is an application for a Beverage antenna?
A. Directional transmitting for low HF bands
B. Directional receiving for low HF bands
C. Portable Direction finding at higher HF frequencies
D. Portable Direction finding at lower HF frequencies
G9D10
Which of the following describes a Beverage antenna?
A. A vertical antenna constructed from beverage cans
B. A broad-band mobile antenna
C. A helical antenna for space reception
D. A very long and low receiving antenna that is highly directional
G9D11
Which of the following is a disadvantage of multiband antennas?
A. They present low impedance on all design frequencies
B. They must be used with an antenna tuner
C. They must be fed with open wire line
D. They have poor harmonic rejection
G9D12
What is the primary purpose of traps installed in antennas?
A. To permit multiband operation
B. To notch spurious frequencies
C. To provide balanced feed-point impedance
D. To prevent out of band operation