Extra exam question E9E05
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9E
What Yagi driven element feed point impedance is required to use a beta or hairpin matching system?
- A.Capacitive (driven element electrically shorter than 1/2 wavelength) (correct answer)
- B.Inductive (driven element electrically longer than 1/2 wavelength)
- C.Purely resistive
- D.Purely reactive
WhyA beta or hairpin matching system requires the Yagi driven element's feed point impedance to be capacitive, meaning the element is electrically shorter than 1/2 wavelength. A beta or hairpin matching system requires the Yagi's driven element to present a capacitive feed point impedance, meaning the element is built electrically shorter than a full half wavelength, since the hairpin's own inductance is specifically there to cancel that capacitive reactance and complete the match, answer A. An inductive (electrically longer) element, a purely resistive impedance, or a purely reactive impedance with no resistive component at all don't match what a beta/hairpin match is designed to correct.
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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