What type of wave propagation is most commonly associated with VHF and UHF frequencies?
VHF and UHF signals primarily travel in straight lines and are affected by line-of-sight obstacles.
Which ionospheric layer is most responsible for long-distance HF communication during the day?
The F2 layer is typically the most significant for HF propagation during daylight hours.
What is modulation in the context of radio transmissions?
Modulation allows information to be encoded onto a carrier wave for transmission.
Which type of modulation varies the amplitude of the carrier wave?
Amplitude Modulation (AM) works by changing the carrier wave’s amplitude to reflect the audio signal.
What happens to radio waves when they encounter the ionosphere?
Radio waves may be absorbed, refracted back to Earth, or pass through, depending on frequency and conditions.
Which of the following frequencies is most likely to be refracted by the ionosphere for long-distance communication?
Lower HF frequencies are more readily refracted by the ionosphere.
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Which type of modulation is known for its resistance to signal noise and interference?
FM is more resistant to amplitude-based noise than AM.
What is a skip zone in radio communication?
A skip zone is an area where no signals are received due to signal bounce and skip patterns.
Which term describes the bending of radio waves around obstacles?
Diffraction is what allows signals to bend around obstructions like buildings and hills.