Which of the following describes an extended double Zepp antenna?
An end-fed full-wave dipole antenna
A center-fed 1.5-wavelength dipole antenna
A center-fed 1.25-wavelength dipole antenna✓Bonne réponse
An end-fed 2-wavelength dipole antenna
Explication
An extended double Zepp is a center-fed wire nominally about 1.25 wavelengths long, so each half is roughly 0.625 wavelength. That sits just under the theoretical optimum of about 0.64 wavelength per side, the point beyond which the broadside lobe splits in two, and the antenna yields roughly 3 dB more broadside gain than a half-wave dipole.