Cardioid Array; Cardioid-Unidirectional With Two Selectable Directions - Hy-Gain AV-18HT Instruction Manual

CARDIOID ARRAY

(Uni-directional)
When two or three identical verticals are ex-
cited directly and fed 90 degrees out of phase
with a spacing of 1/4 wave length, a cardioid
pattern results. This pattern may be switched in
either direction. By inserting a 1/4 wave length
delay line the antenna will "fire" or be directive
to that particular element. .:
TWO VERTICALS
Figure 3

Cardioid-Unidirectional With Two Selectable Directions