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Question 20243
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Principles of Communication: Antenna MCQ

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AntennaMediumQuestion 20243

Question

The minimum antenna height required to radiate a signal of wavelength λ efficiently is:
  1. A
    λ
  2. B
    λ/4
    Correct
  3. C
    λ/2
  4. D
    2λ

Correct answer

λ/4

Explanation

A quarter-wave monopole above a ground plane (or half-wave dipole) is the minimum for efficient radiation. The ground plane provides the other quarter-wave image. At 1 MHz (AM), λ/4 = 75 m; at 100 MHz (FM), λ/4 = 0.75 m.

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