High power VLF transmitting antennas using fast wave horizontal dipole arrays

Horizontal VLF transmitting dipole arrays are much easier and less expensive to construct than are the vertical VLF transmitting antennas in use at the present time. The horizontal dipoles have much greater power-radiating capability and bandwidth. The theoretical and experimental effects of mutual resistance on array efficiency gain over one dipole are presented. The radiation efficiency is greatly increased by increasing the wave velocity along the resonant dipole. Radiation characteristics of a theoretical 18-dipole array on Hawaiian lava are shown. The antenna radiation pattern needed to get omnidirectionl coverage at VLF is presented. It is shown that directivity is needed because of the nonreciprocal east-west propagation attenuation.