Extra exam question E9A10
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9A
Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?
- A.Installing a ground radial system (correct answer)
- B.Isolating the coax shield from ground
- C.Shortening the radiating element
- D.All these choices are correct
WhyInstalling a ground radial system improves the efficiency of a ground-mounted quarter-wave vertical antenna. Installing a ground radial system improves the efficiency of a ground-mounted quarter-wave vertical by providing a low-loss return path for antenna current, reducing the resistive losses that would otherwise occur in lossy native soil, answer A. Isolating the coax shield from ground and shortening the radiating element don't improve efficiency the way a proper radial system does, and since only the radial system option is genuinely correct, "all these choices" overstates it.
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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