The basic description of the Lightning Field is accurate: a perfect grid of steel poles one mile x one kilometer. In addition, the steel poles have sharply pointed tips and vary in height (depending on their location on the terrain) so that the tip of each pole is at the same height. If a pane of glass were laid over the grid of poles, each pole tip would touch the pane of glass.
Each pole is separately grounded so that a lightning strike, should it occur, would not arc from pole to pole.
It is A rectangular grid in New Mexico measuring one mile by one kilometer and containing 400 stainless-steel lightning rods, it serves as an arena for observing meteorological activity.