Extra exam question E9D05

WhyA Yagi's driven element is approximately 1/2 wavelength long. A Yagi's driven element is approximately a half wavelength long, the same basic resonant length as an ordinary dipole, before the parasitic elements and mutual coupling shift its exact length and impedance slightly, answer D. The formulas involving 234 or 1005 divided by frequency describe quarter-wave and other specific calculations, not the driven element's basic half-wavelength starting point, and a quarter wavelength describes a different kind of element entirely.