Radiodetection T631 TDR - Dielectric Constant (Permittivity) Known; Short Length of Same Type of Cable

Ifthe valueof the PVF or thecable type isnot known thenthe PVF can be determined as follows.
7.4.2 DIELECTRIC CONSTANT (PERMITTIVITY) KNOWN
PVF =
1
ε
Example: For polyethylene ε = 2.25
PVF ==
1
225
0667
.
.
7.4.3 SHORT LENGTH OF SAME TYPE OF CABLE
1. Measure physical length of the sample.
2. Obtain a reading for the apparent length of the cable using any PVF value.
3. Adjust the PVF value until the distance reading indicated is the same as the measured
length.
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T631 OPERATING MANUAL 26