Podcast
Questions and Answers
What is the measure of an antenna's directivity?
What is the measure of an antenna's directivity?
- Effective radiated power
- Radiation pattern
- Antenna gain
- Beam width (correct)
How is the beam width of an antenna measured?
How is the beam width of an antenna measured?
- Between the points on the radiation curve that are 15 dB down from the maximum amplitude
- Between the points on the radiation curve that are 10 dB down from the maximum amplitude
- Between the points on the radiation curve that are 6 dB down from the maximum amplitude
- Between the points on the radiation curve that are 3 dB down from the maximum amplitude (correct)
How is antenna gain usually expressed?
How is antenna gain usually expressed?
- As a ratio of the effective radiated output power to the input power
- In decibels (correct)
- In watts
- In milliwatts
What is the impedance of a dipole antenna at its center?
What is the impedance of a dipole antenna at its center?
What is the purpose of the insulators in a wire dipole antenna?
What is the purpose of the insulators in a wire dipole antenna?
What is the purpose of the transmission line in a dipole antenna?
What is the purpose of the transmission line in a dipole antenna?
What happens when a radio wave encounters a perfect conductor?
What happens when a radio wave encounters a perfect conductor?
Which type of surfaces can cause reflection of radio waves?
Which type of surfaces can cause reflection of radio waves?
What happens to a radio wave when it encounters a good conductor?
What happens to a radio wave when it encounters a good conductor?
What causes refraction of a radio wave?
What causes refraction of a radio wave?
What is the effect of a poor conductor on a radio wave?
What is the effect of a poor conductor on a radio wave?
How does the degree of bending of a radio wave during refraction relate to the medium's index of refraction?
How does the degree of bending of a radio wave during refraction relate to the medium's index of refraction?
What is the reason a radio signal is called an electromagnetic wave?
What is the reason a radio signal is called an electromagnetic wave?
In a wire antenna, what happens when voltage is applied?
In a wire antenna, what happens when voltage is applied?
How are the electric and magnetic fields emitted from the antenna?
How are the electric and magnetic fields emitted from the antenna?
What do transmission lines, unlike antennas, not efficiently do?
What do transmission lines, unlike antennas, not efficiently do?
What happens to the direction of the electric field between wires in a transmission line during one-half cycle of the ac input?
What happens to the direction of the electric field between wires in a transmission line during one-half cycle of the ac input?
How does the strength of a magnetic field produced by a wire antenna relate to the strength of an electric field produced?
How does the strength of a magnetic field produced by a wire antenna relate to the strength of an electric field produced?
What is the index of refraction for air?
What is the index of refraction for air?
What happens when an incident wave from a transmitter travels through air and meets a region of ionized air?
What happens when an incident wave from a transmitter travels through air and meets a region of ionized air?
What is Snell's law related to?
What is Snell's law related to?
What is a shadow zone?
What is a shadow zone?
What is the main signal path for radio signals in the 30-kHz to 3-MHz range?
What is the main signal path for radio signals in the 30-kHz to 3-MHz range?
What type of polarization is required for ground waves to be propagated from an antenna?
What type of polarization is required for ground waves to be propagated from an antenna?
Which of the following layers of the ionosphere are weakly ionized and exist only during daylight hours?
Which of the following layers of the ionosphere are weakly ionized and exist only during daylight hours?
What is the primary effect of the F layer on radio signals?
What is the primary effect of the F layer on radio signals?
What happens when a radio signal goes into the ionosphere?
What happens when a radio signal goes into the ionosphere?
Which statement is true about radiation directly vertical from the antenna?
Which statement is true about radiation directly vertical from the antenna?
What happens to radio signals at very high frequencies above about 50 MHz?
What happens to radio signals at very high frequencies above about 50 MHz?
What is the result of reflected radio waves being sent back to Earth with minimum signal loss?
What is the result of reflected radio waves being sent back to Earth with minimum signal loss?
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