30
4-55. A unidirectional pattern can be obtained
from an end-fire array by using what
phase relationship between the energy
fed to adjacent elements?
1. 0º
2. 45º
3. 90º
4.
180º
4-56. Energy is fed to a parasitic element using
what method?
1. Direct coupling
2. Inductive coupling
3. Capacitive coupling
4. Transmission-line coupling
4-57. The directivity pattern resulting from the
action of parasitic elements depends on
which of the following element
characteristics?
1. Length of the element
2. Diameter of the element
3. Spacing between parasitic and driven
elements
4. Each of the above
4-58. The advantages of unidirectivity and
increased gain can best be obtained by
using which of the following elements in
a parasitic array?
1. Driven elements only
2. Reflector and director elements only
3. Reflector, director, and driven
elements
4. Driven and director elements only
4-59. The ratio of energy radiated by an array
in the principal direction of radiation to
the energy radiated in the opposite
direction describes which of the
following relationships?
1. Side-to-side ratio
2. Front-to-back ratio
3. Driven-to-parasitic ratio
4. Reflector-to-director ratio
4-60. The Yagi antenna is an example of what
type of antenna array?
1. Driven
2. End-fire
3. Multielement parasitic
4. Single-element parasitic
4-61. The addition of parasitic elements to the
Yagi antenna has which of the following
effects on antenna characteristics?
1. Increased gain
2. Narrower beam width
3. Narrower frequency response
4. Each of the above
4-62. An antenna which is designed especially
for vertically-polarized ground waves at
low frequencies is the
1. Yagi antenna
2. Marconi antenna
3. Beverage antenna
4. V antenna
4-63. What is the phase relationship of the
signals that feed the V antenna?
1. 0º
2. 45º
3. 90º
4.
180º
4-64. A rhombic antenna is essentially a
combination of which of the following
antennas?
1. Two stacked long-wire radiators
2. Two V antennas placed side by side
3. Two collinear arrays in parallel
4. Four parallel half-wave radiators
4-65. A rhombic antenna has which of the
following advantages?
1. Simple construction
2. Wide frequency range
3. Noncritical adjustment
4. Each of the above
