Monopolar vertically-polarised logarithmic short-wave antenna - achieves broad bandwidth by using supply transformers matched to inductance of radiators

摘要

The antennae has a coaxial supply cable whose outer conductor is connected to a ground network while the inner conductor is connected to the radiators. Only every second radiator is directly connected to the cable's inner conductor. The remaining radiators are connected via transformers to the inner conductor. The polarity of the transformer couplings is chosen so that the radiators are in opposite phase. - The inductance of the transformers for the shorter radiators is less than that calculated from theory whilst the inductance of the transformers for the longer radiators is greater than that calculated from theory. The advantage lies in smallness and quick assembly.