Extra exam question E9A04
Subelement E9, ANTENNAS AND TRANSMISSION LINES· Group E9A
Which of the following factors affect the feed point impedance of an antenna?
- A.Transmission line length
- B.Antenna height (correct answer)
- C.The settings of an antenna tuner at the transmitter
- D.The input power level
WhyAntenna height affects an antenna's feed point impedance. An antenna's feed point impedance is affected by its height above ground, since ground reflections interact with the antenna's near field and shift the impedance the antenna actually presents at its feed point, answer B. Transmission line length, an antenna tuner's settings at the transmitter, and the input power level don't change the antenna's own feed point impedance, they affect how that impedance appears elsewhere in the system or how it's matched, not the antenna's inherent feed point value.
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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