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This article in VZJ

  1. Vol. 1 No. 2, p. 316-319
    Received: Feb 21, 2002

    * Corresponding author(s): magnus.persson@tvrl.lth.se
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Shaft-Mounted Time Domain Reflectometry Probe for Water Content and Electrical Conductivity Measurements

  1. Magnus Persson *a and
  2. Jon M. Wraithb
  1. a Dep. of Water Resources Engineering, Lund University, Box 118, SE-221 00 Lund, Sweden
    b Land Resources and Environmental Sciences, Montana State University, P.O. Box 173120, Bozeman, MT 59717-3120


A new shaft-mounted time domain reflectometry (TDR) probe design is described and evaluated. In contrast to previous shaft-mounted TDR probes (SMPs), the new design may be used to measure both dielectric constant (K a) and bulk electrical conductivity (σa). Two SMP prototypes, 0.03 and 0.04 m long and having diameters of 0.006 m, were evaluated. The probes were calibrated in several fluids having different K a and σa A primary advantage of the SMP is minimal physical probe length without sacrificing accuracy of K a readings. Accuracy of K a measurements for the new probes was similar to that of standard 0.20-m-long three-rod probes.

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Copyright © 2002. Soil Science SocietyPublished in Vadose Zone Journal1:316–319.