General exam question G9C04
Subelement G9, ANTENNAS AND FEED LINES· Group G9C
How does antenna gain in dBi compare to gain stated in dBd for the same antenna?
- A.Gain in dBi is 2.15 dB lower
- B.Gain in dBi is 2.15 dB higher (correct answer)
- C.Gain in dBd is 1.25 dBd lower
- D.Gain in dBd is 1.25 dBd higher
WhyAntenna gain in dBi is 2.15 dB higher than gain stated in dBd for the same antenna. Gain measured in dBi (referenced to a theoretical isotropic radiator) is always 2.15 dB higher than the same antenna's gain measured in dBd (referenced to a real dipole), because a dipole itself already has about 2.15 dBi of gain over an isotropic radiator, answer B. It isn't 2.15 dB lower, and the dBd-referenced comparisons in C and D use the wrong figure (1.25 dB) entirely, so A, 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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