Amateur radio operators tend to use the NEC-calculated far-field analysis almost exclusively. However the far field as defined in antenna engineering textbooks begins at a distance of about 2L²/λ meters [L = Radiator Length(Height), in meters; λ = wavelength, in meters]. Note that at the distance of 1 kilometer specified for the e-fields of the NEC calculations shown below, both the far-field and the surface-wave values lie in far-field of that radiator. Using only the NEC far-field pattern to analyze the performance of a vertical monopole antenna system driven against a lossy ground plane can lead to a belief that it has zero radiation in the horizontal plane, and not much more than zero at very low elevation angles. However that is not always the case, when NEC analyzes the surface wave at ranges within distances of 30 miles or even more from the antenna site (depending on radiated power, frequency, ground plane conductivity etc).