General exam question G9B08
Subelement G9, ANTENNAS AND FEED LINES· Group G9B
How does the feed point impedance of a 1/2 wave dipole change as the feed point is moved from the center toward the ends?
- A.It steadily increases (correct answer)
- B.It steadily decreases
- C.It peaks at about 1/8 wavelength from the end
- D.It is unaffected by the location of the feed point
WhyA 1/2 wave dipole's feed point impedance steadily increases as the feed point is moved from the center toward the ends. A half-wave dipole's feed point impedance is lowest at the center (around 70 ohms) and rises steadily as the feed point is moved out toward the high-voltage, low-current ends of the antenna, answer A. It doesn't steadily decrease moving outward, doesn't peak partway out at 1/8 wavelength from the end, and feed point location clearly does change the impedance, so B, C, and D are 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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