Formulae are developed for the far-field radiation patterns of end-fire arrays of magnetic line sources mounted on the surface of a half-plane. Patterns have been plotted for a number of interesting cases. It is found that the Hansen–Woodyard optimum end-fire condition no longer holds when the array is near the edge of the half-plane. The theory seems to describe reasonably well the behavior of corrugated surface radiators embedded in a finite ground plane, providing the array is removed from the edge by a distance about equal to the array length.