VLF modal interference distance for a west-east propagation path to Fiji

摘要

Pronounced amplitude minima are observed on 19.8 kHz signal recorded at Suva (18.149°S, 178.446°E), Fiji, from a VLF navigational transmitter located in North West Cape (NWC), Australia. The propagation path is mixed over land and sea having Transmitter-Receiver Great Circle Path distance 6.7 Mm. In this paper the modal interference distance (DMS) for west-east propagation path (NWC-Suva) has been estimated using Terminator Time method which is based on the measure and analysis of the occurrence times of amplitude minima. The experimental values of DMS were found to be consistent with the theoretical values calculated using the mode theory of VLF wave propagation in the Earth-ionosphere waveguide.