All measurements are taken from the center of the accessory and extend outward in both directions along the X and Y axes. The center point is labeled 0mm, with distances increasing symmetrically toward the edges.
The field is measured on a grid. Starting at the center, the test engineer steps a probe outward along each axis at a fixed point spacing, taking a reading at every point, and continues a little past the accessory edge to catch the field as it fades. The origin is the center of the accessory surface.
