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Question 20313
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Principles of Communication: Propagation MCQ

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PropagationEasyQuestion 20313

Question

Which propagation mode is used by standard AM (medium-wave) radio broadcast stations?
  1. A
    Space wave only
  2. B
    Ground wave (with some sky wave at night)
    Correct
  3. C
    Satellite wave
  4. D
    Guided wave in cable

Correct answer

Ground wave (with some sky wave at night)

Explanation

AM (530–1710 kHz) propagates as ground wave during the day (range ~500 km). At night, the D layer disappears and sky-wave propagation takes over, extending range to thousands of kilometres — that's why distant AM stations can be received at night.

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