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Antennas practice questions

26 questions from the amateur radio (technician) practice test.

Antennas practice test

10 questions, graded as you go, with the reason for every answer. No sign-up.

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Sample questions

A half-wave dipole is strung parallel to the ground. What is the polarization of its signal?

  1. Vertical
  2. Circular
  3. Horizontal
  4. Elliptical
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C. Horizontal

Polarization follows the orientation of the radiating element's electric field, so a horizontal wire radiates a horizontally polarized wave. Turning the same dipole upright would make it vertical.

Reference: Antenna fundamentals: polarization

In which directions does a half-wave dipole in free space radiate most strongly?

  1. Off the two ends of the wire
  2. Broadside to the wire
  3. Equally in every direction
  4. Straight up and down only
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B. Broadside to the wire

A dipole's pattern is strongest at right angles to the wire and has nulls off its ends. Only a theoretical isotropic antenna radiates equally in all directions.

Reference: Antenna fundamentals: dipole pattern

What is the main feature of a beam antenna such as a Yagi?

  1. It radiates equally well in all directions
  2. It works on every band without adjustment
  3. It needs no feed line between it and the radio
  4. It concentrates the signal in one direction
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D. It concentrates the signal in one direction

A beam focuses transmitted energy, and receiving sensitivity, in one direction, giving gain and rejecting signals from other directions. Radiating equally around the compass describes an omnidirectional vertical.

Reference: Antenna fundamentals: directional antennas

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