General exam question G9C03
Subelement G9, ANTENNAS AND FEED LINES· Group G9C
How do the lengths of a three-element Yagi reflector and director compare to that of the driven element?
- A.The reflector is longer, and the director is shorter (correct answer)
- B.The reflector is shorter, and the director is longer
- C.They are all the same length
- D.Relative length depends on the frequency of operation
WhyIn a three-element Yagi, the reflector is longer than the driven element and the director is shorter. In a three-element Yagi, the reflector behind the driven element is cut slightly longer than the driven element, and the director in front is cut slightly shorter, that length difference is exactly what makes them act as a reflector and director through mutual coupling, answer A. The relationship isn't reversed (B), the elements aren't all equal length (C), and while the specific length differences scale with the design frequency, which element is longer versus shorter doesn't flip depending on frequency, so D is also wrong.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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