Let’s understand how phased verticals work so we can explain it to others.
Our Quadrature Set Up
Two identical 1/4-wavelength verticals are spaced 1/4-wavelength apart and fed through a relay that adds an extra piece of cable into one of the vertical’s feedlines. When the relay energizes, the extra cable goes into the other vertical’s feedline. The spacing and extra cable provide the spatial and temporal delays needed to phase the verticals in quadrature.1
Creating the Spatial Delay
The spatial delay comes from spacing the verticals 1/4-wavelength apart. When excited by the same signal, the electric fields emitted by each vertical arrive at the other vertical 90º behind the excitation signal. Click the image to understand.
Over the time it takes these electric fields to span the 1/4-wavelength gap between the verticals, the excitation signal advances 90º of its 360º oscillation. This causes both verticals to be surrounded by electric fields that are 90º behind those they, themselves, are radiating.
Creating the Temporal Delay
After this, all we have to do is delay the signal being fed to one of the verticals. This is accomplished by inserting an extra 1/4-wavelength of cable into its feedline. This delays the signal feeding the vertical by 90º which causes it to now be in-phase with the electric fields sent to it from the other vertical. That vertical, in turn, now perceives the electric fields from the delayed vertical as being 180º out-of-phase with its excitation signal.
This Changes the Aerials Pattern
The electric fields around the “out-of-phase” vertical cancel each other out, producing the null in the phased vertical radiation pattern.2 Electric fields around the “in-phase” vertical add-up, producing its broad, forward lobe. When the relay is energized, the verticals exchange roles which reverses the array’s directivity.3
This might be the most straightforward way for readers to explain how their phased verticals work to others during on-air demonstrations.
Which essentially means “quarters”. Everything has to do with 90º.
By “the electric fields” we mean (i) the electric field which has traveled from the other vertical, and (ii) the electric field being radiated by the vertical.
The array points in the direction of the vertical with the extra cable in its feedline.
Well written and easy to follow