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When an open-circuited section of unshielded balanced two-wire transmission line is introduced perpendicularly into earth (or some sample under test), the electrical characteristics of the latter may be found by simple input-impedance measurements. By laboratory sample measurements the classical short- and open-circuited method can be used. Some exact and approximate procedures are presented and their utility and practical limitations discussed. Some precautions as to how possible errors and inexactnesses in the measurements and following calculations may be avoided are given. As an example, a typical earth sample is tested in a frequency range from 0.6 to 400 mc, with graphic representation of the most important electrical constants: conductivity, dielectric constant, attenuation, velocity of propagation, etc., which exhibit great variations in the frequency range cited. The measurement method presented seems to be adequate to use in small mobile equipment, with which the ground in general can be tested in its original site and under natural conditions without the necessity of being removed.
Date of Publication: May 1960