'Peninsula impedance measurements’ in the Marlborough Sounds, New Zealand

Measurements have been made of the input impedance, at VLF, of a series of transmission lines connected across a peninsula in the Marlborough Sounds, New Zealand. No resonances in the input impedance have been found which cannot be explained in terms of basic earth-return transmission line theory, the surrounding sea serving only to provide low impedance line terminations. In contrast to the assertions of Morgan (1980), the phase velocity of propagation along the earth-return transmission lines has been found to decrease markedly as the cables are lowered to the earth's surface. It is concluded that the ‘peninsula’ and ‘island’ resonances observed near 10 kHz by Gould (1961) and Morgan (1979) were simply cable resonances, the phase velocity along the cables having been reduced by their proximity to the ground.