Amateur Extra › E9 Antennas and Transmission Lines › E9C02
E9C02
What type of radiation pattern is created by two 1/4-wavelength vertical antennas spaced 1/4-wavelength apart and fed 90 degrees out of phase?
Pick an answer to check it.
Answer: A. Cardioid
Quarter-wave spacing with 90 degree phasing makes signals add in one direction and cancel in the opposite direction. That produces a heart-shaped cardioid pattern.
Tip: Quarter wave, 90 degrees = cardioid.