The two horizontal directions used to measure the magnetic field across the accessory surface. The X-axis and Y-axis cross at the center of the accessory. Measurements extend outward from center in both directions along each axis. In some configurations, both axes may reflect the same value, indicating a symmetrical field.
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.
