Intro

This is the second post on phased verticals. If you have not seen the first, here it is >>Half-square antenna....
After half-square antenna, I checked few similar configurations, adding phasing lines and vertical elements. Here is the popular antenna, usually called "double half-square":

As you see, it is basically 2 half-square antennas put together and fed in the center. The length of the phasing lines is still L/2, so left and right radiators emit in phase: