Antennas: vertical and horizontal polarization, concept of antenna gain, definition and types of beam antennas, antenna loading, common portable and mobile antennas, relationships between resonant length and frequency, dipole pattern
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T9A01
What is a beam antenna?
AAn antenna built from square aluminum beams
BAn omnidirectional antenna invented by Clarence Beam
CAn antenna that concentrates signals in one direction
DAn antenna that focuses the signal into two intense rays
T9A02
Which of the following describes a type of antenna loading?
AElectrically lengthening by inserting inductors in radiating elements
BInserting a resistor in the radiating portion of the antenna to make it resonant
CInstalling a spring in the base of a mobile vertical antenna to make it more flexible
DStrengthening the radiating elements of a beam antenna to better resist wind damage
T9A03
How is the polarization of an antenna described?
ABy the shape of the driven element
BBy the orientation of the electric field
CBy the orientation of the magnetic field
DBy the direction of radiation
T9A04
What is a disadvantage of a handheld radio transceiver's short flexible antenna compared to a full-sized quarter-wave antenna?
AIt has low efficiency
BIt transmits only circularly polarized signals
CIt is more susceptible to receiver desensitization
DIt only works on analog signals, not digital ones
T9A05
Which of the following increases the resonant frequency of a dipole antenna?
ALengthening it
BInserting coils in series with radiating wires
CShortening it
DAdding capacitive loading to the ends of the radiating wires
T9A06
Which of the following types of antennas offers the greatest gain?
A5/8 wave vertical
BIsotropic
CJ pole
DYagi
T9A07
What is a potential drawback of using a handheld VHF transceiver inside a vehicle that lacks an externally mounted antenna?
ASignal strength is reduced due to the shielding effect of the vehicle
BThe bandwidth of the antenna will decrease, increasing SWR
CThe SWR might decrease, decreasing the signal strength
DThe handheld will overheat due to reflected power in the vehicle
T9A08
Why is a 19-inch-long vertical antenna often used on 2 meters?
AIt has high gain
BIt is a resonant half-wave
CIt is a resonant quarter-wave
DIt has low RF radiation exposure
T9A09
What is an advantage of a 5/8-wavelength whip antenna for VHF or UHF mobile service compared to a 1/4-wave antenna?
AIt has more gain
BIt radiates at a higher angle
CIt has lower SWR
DIt has lower impedance
T9A10
In which direction does a half-wave dipole antenna radiate the strongest signal?
AEqually in all directions
BOff the ends of the antenna
CIn the direction of the feed line
DBroadside to the antenna
T9A11
What is antenna gain?
AThe additional power that is added to the transmitter power
BThe additional power that is required in the antenna when transmitting on a higher frequency
CThe increase in signal strength in a specified direction compared to a reference antenna
DThe increase in impedance on receive or transmit compared to a reference antenna