Extra exam question E9C03
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9C
What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/2- wavelength apart and fed in phase?
- A.Omni-directional
- B.Cardioid
- C.A figure-eight broadside to the axis of the array (correct answer)
- D.A figure-eight end-fire along the axis of the array
WhyTwo 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed in phase create a figure-eight pattern broadside to the axis of the array. Two quarter-wave verticals spaced a half-wavelength apart and fed in phase produce a figure-eight pattern broadside to the axis of the array, with the strongest radiation perpendicular to the line connecting the two elements, answer C. It isn't omnidirectional or cardioid, and the figure-eight lobes point broadside, not end-fire along the array's axis, in this in-phase, half-wave-spacing combination.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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