Uncertainty in radiated tests due to source polarization

Radiated uncertainty calculations are based on instrumentation and transducer factors for testing at a site that conforms to normalized site attenuation criteria, such as ANSI C63.4. The criterion is obtained using linear polarized antennas to measure like polarized sources. Equipment testing or troubleshooting generally conforms to this model, but some very substantial vertical signals can be generated by a horizontal source when equipment under test is rotated 90°. A vertical signal emitted from a horizontal source is a departure from normal conceptions and could be a source of uncertainty. This paper reports measured data from a horizontal source antenna positioned at quadrature to a vertical antenna and presents a condition of uncertainty (not an error) in the confidence of a vertical measurement on equipment under test.