A near-field to far-field transformation technique with helicoidal scanning for elongated antennas, which allows
the evaluation of the antenna far-field pattern in any cut plane directly from a nonredundant number of near-field data
without interpolating them, is developed in this paper. It is based on the nonredundant sampling representations of
electromagnetic fields and employs a flexible source modelling suitable for long antennas to determine the number of
helix turns. The number of near-field measurements on each turn is on the contrary dictated by the minimum cylinder rule,
as in the classical cylindrical scanning, in order to reduce the computational burden and to simplify the scanning from the
mechanical viewpoint. Some numerical and experimental results assessing the effectiveness of the proposed technique are
reported.