T9A-2010: Antennas; vertical and horizontal, concept of gain, common portable and mobile antennas, relationships between antenna length and frequency
T9A01:
What is a beam antenna?
An antenna that concentrates signals in one direction
An antenna built from aluminum I-beams
An omnidirectional antenna invented by Clarence Beam
An antenna that reverses the phase of received signals
T9A02:
Which of the following is true regarding vertical antennas?
The electric field is perpendicular to the Earth
The magnetic field is perpendicular to the Earth
The phase is inverted
The phase is reversed
T9A03:
Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth’s surface?
A horizontally polarized antenna
A ground wave antenna
A rhombic antenna
A vertically polarized antenna
T9A04:
What is a disadvantage of the "rubber duck" antenna supplied with most handheld radio transceivers?
It does not transmit or receive as effectively as a full-sized antenna
It transmits a circularly polarized signal
If the rubber end cap is lost it will unravel very quickly
All of these choices are correct
T9A05:
How would you change a dipole antenna to make it resonant on a higher frequency?
Shorten it
Lengthen it
Insert coils in series with radiating wires
Add capacity hats to the ends of the radiating wires
T9A06:
What type of antennas are the quad, Yagi, and dish?
Directional antennas
Non-resonant antennas
Loop antennas
Isotropic antennas
T9A07:
What is a good reason not to use a "rubber duck" antenna inside your car?
Signals can be significantly weaker than when it is outside of the vehicle
It might cause your radio to overheat
The SWR might decrease, decreasing the signal strength
All of these choices are correct
T9A08:
What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?
19
112
50
12
T9A09:
What is the approximate length, in inches, of a 6 meter 1/2-wavelength wire dipole antenna?
112
6
50
236
T9A10:
In which direction is the radiation strongest from a half-wave dipole antenna in free space?
Broadside to the antenna
Equally in all directions
Off the ends of the antenna
In the direction of the feedline
T9A11:
What is meant by the gain of an antenna?
The increase in signal strength in a specified direction when compared to a reference antenna
The additional power that is added to the transmitter power
The additional power that is lost in the antenna when transmitting on a higher frequency
The increase in impedance on receive or transmit compared to a reference antenna
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