The intelligent and compact TRIME-PICO IPH/T3 sensor is a measurement devices for continuous and non-destructive determination of volumetric soil moisture. It is designed for mobile field use and can be connected to a PICO-BT Bluetoothmodule or a data logger (globeLog or any analogue data logger) or a PC for monitoring and data logging purposes. 
IMKO was the first manufacturer of TDR measuring techniques to offer a TDR tube access probe especially designed for water content profiling. For the first time ever, the rapid, routine and non-destructive measurements of water content profiles is possible without the use of hazardous radioactive materials. The tube probe consists of a cylindrical PVC-body, which has four spring-mounted aluminium plates as TDR wave guides on opposite sides.

The measurements are performed from within TECANAT plastic access tubes which can be left in the soil. The tubes must be installed prior to the taking the measurements by using a specially developed drilling set. The system enables cable lengths of up to 25m. The intelligent, automatic TDR-curve reading electronics is housed in a robust and waterproof (IP-68) PVC-cylinder, withstanding even the toughest demands of permanent field use. The low power consumption of 8mA stand-by and 100mA during the 2..3-second measuring period conserves your power resources on site. Features are a RS485/V24 interface for both an external power supply (7V..24V/DC, 100mA) and connecting the PICO-BT Bluetoothmodule or a PC as well as an 0..1V or 0(4)..20mA analogue output for interfacing external devices e.g. datalogger.

The operating principle 
The TRIME device generates a high-frequency pulse (up to 1GHz) which propagates along the metal shells, generating an electromagnetic field around the probe. At the end of the shells, the pulse is reflected back to its source. The resulting transit time (3ps...2ns!) can be measured and enabling determination of the propagation velocity, which is primarily dependent on the water content. The volumetric water content is then calculated by the velocity and is shown on the display panel immediately.

Measuring volume 
The effective penetration depth of the probe T3 is about 15 cm with the highest sensitivity in the immediate vicinity of the access tube, and decreases exponentially as distance increases.