Monopolar logarithmic-periodic short wave aerial - has lengths of radiators coupled to supply lead via transformers shortened by length of transmitter lead

摘要

A vertically-polarised, logarithmically-tunable shortwave antenna is such that the individual antenna radiator sections are connected to the coaxial feeder cable alternately by direct galvanic coupling and antiphase inductive (transformer) coupling. Perfect standing waves are maintained in the antenna in spite of the unequal radiation resistance of the galvanically-and-transformer-coupled elements. The method of correction is based on making the effective radiation lengths equal. This implies that the inductively-coupled radiator sections must be shortened by an amount equal to the effective radiation length of the transformer. DS.