General exam question G9C07
Subelement G9, ANTENNAS AND FEED LINES· Group G9C
What does “front-to-back ratio” mean in reference to a Yagi antenna?
- A.The number of directors versus the number of reflectors
- B.The relative position of the driven element with respect to the reflectors and directors
- C.The power radiated in the major lobe compared to that in the opposite direction (correct answer)
- D.The ratio of forward gain to dipole gain
WhyFront-to-back ratio refers to the power radiated in a Yagi's major lobe compared to that in the opposite direction. Front-to-back ratio compares how much power the antenna radiates in its main forward lobe against how much leaks out in the opposite (rearward) direction, a measure of how well the antenna rejects signals and interference from behind it, answer C. It isn't a count of directors versus reflectors, isn't about the driven element's physical position, and isn't a ratio of forward gain to dipole gain (that's what dBd gain itself already measures), so A, B, 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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