Plain-language answer: The radiating near field, or Fresnel region, lies beyond the mainly reactive region but before angular field distribution becomes independent of distance.
Why it changes the path
Radiation is important there, yet wavefront curvature and field pattern still vary with observation distance, especially for electrically large antennas.
What to observe
Use the appropriate distance and geometry for range testing, and document both antenna dimensions and observation point.
The common mistake
Assuming a few wavelengths is always enough for far-field pattern measurement.
Planning boundary
Propagation models and field regions depend on frequency, geometry, terrain, atmosphere, polarization, antenna pattern, and measurement distance. Use them to plan and compare—not to guarantee a contact or installed range.
