Accurate determination of the bulk electrical conductivity with the TDR100 cable tester.

摘要: Time domain reflectometry (TDR) is commonly used to determine the soil bulk electrical conductivity. To obtain accurate measurements, three parameters of a series resistor model (probe constant, K p ; cable resistance, R c and remaining 0 ) are typically calibrated using liquids with known Several studies have reported discrepancies between directly measured model. In this study, we examined possibility that technical issue TDR100 tester contributed part these inconsistencies. Our results showed an increasing level waveform averaging, reflection coefficient, as well , C approached maximum value. A comparison independently determined values indicated high averaging provided physically most plausible results. Based on our results, propose at least 16 waveforms, each consisting 250 points. An oscilloscope-based signal analysis increase in coefficient saline media related capacitance associated electrode polarization combination change pulse period train when starts collecting data This resulted slow average voltage TDR until stable was reached. Higher levels cancel impact first erroneous measurements out. practical applications, errors determination conductivity can be 5% for low-conductivity range (<0.1 S m -1 up 370% (1.4 changed after calibration.