Using Dispersion to Measure Ground Conductivity
BCRA: British Cave Research Association
Open access under a Creative Commons CC-BY-NC licence.
Several methods of remotely measuring ground conductivity are known, which depend on measuring the amplitude and phase of a received signal, relative to its transmitter. All of these methods require the separate transmission of a phase reference signal, with attendant difficulties. David Gibson proposes that by transmitting a suitably constructed signal, a phase measurement may be made without the need for a separate reference. This is achieved by making use of the phenomenon of dispersion, in which the phase velocity of a wave depends on its frequency. A related technique that makes relative measurements of signal amplitude is also described.
This is the final version of the article. Available from BCRA via the URL in this record.
Vol. 85, pp. 7-8, 19