Omni-azimuthal pattern generator for VLF and LF communication

摘要

A relative phase shift is induced in the signals of a pair of identical orthogonal antennas such that when the signals are combined the signals are 90 degrees out of phase. This is done in order to eliminate the null along the axis between the two dipole moments of the antennas such that the system has equally good reception from all azimuth angles over a broad range of frequencies. The phase shift is accomplished with the use of single pole operational amplifier circuits whose pole frequencies are adjusted by means of a potentiometer prior to implementation of the antenna system.