General exam question G9D11
Subelement G9, ANTENNAS AND FEED LINES· Group G9D
Which of the following is a disadvantage of multiband antennas?
- A.They present low impedance on all design frequencies
- B.They must be used with an antenna tuner
- C.They must be fed with open wire line
- D.They have poor harmonic rejection (correct answer)
WhyA disadvantage of multiband antennas is poor harmonic rejection. A multiband antenna, by design, has to present a usable match across several unrelated frequency ranges at once, which generally comes at the cost of poorer rejection of harmonics that fall within one of those other design bands, answer D. Multiband designs don't inherently present low impedance on every design frequency, don't strictly require an antenna tuner (many are designed to work without one), and don't require open-wire feed specifically, so A, B, and C 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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