E9C01 — Amateur Extra Class

E9C01 : What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/2-wavelength apart and fed 180 degrees out of phase?
A Cardioid
B Omni-directional
C A figure-eight broadside to the axis of the array
D A figure-eight oriented along the axis of the array
Correct Answer: A figure-eight oriented along the axis of the array