The TDR100 Time-Domain Reflectometer is the core of the Campbell Scientific time-domain reflectometry system. This system is used to accurately determine soil volumetric water content, soil bulk electrical conductivity, rock mass deformation, or user-specific time-domain measurement. Up to 16 TDR100s can be controlled using a single Campbell Scientific data logger. PC-TDR software is used with our TDR100-based systems during system setup and troubleshooting. It can be downloaded from the Downloads section of the web page.