
 | Description Hydra Probe II soil moisture, temperature, & salinity sensor, SDI-12 interface, 25' cable.
Features Instantaneous sensor response with no calibration requirements Compact, rugged, zero-maintenance design for long-term deployments Easy integration with NexSens data logging & telemetry products

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Details:
Stevens patented hydra probe design is unique compared to other soil moisture probes because the electrical response of soils can be specified by two parameters - the dielectric constant and the conductivity.
The dielectric constant is most indicative of water content, while the conductivity is strongly dependent on soil salinity. Unlike other capacitance type sensors, the hydra probe measures both of these components simultaneously. The high frequency electrical measurements indicating the capacitive and conductive properties of soil are then directly related to the soil's moisture and salinity content, while a thermistor determines soil temperature.
Notable Specifications:
Dielectric Constant Range: 1 to 65 where 1 = Air, 78 = Distilled Water
Dielectric Constant Accuracy: +/- 1.5% or +/- 0.2 whichever is typically greater
Soil Moisture Range: From completely dry to fully saturated
Soil Moisture Accuracy: +/- 0.03 water fraction by volume in typical soil
Conductivity Range: 0-20 dS/m
Conductivity Accuracy: +/- 2.0% or +/- 0.002 dS/m whichever is typically greater
Temperature Range: -10 to +65 C
Temperature Accuracy: +/- 0.6 C
Operating Temperature In soils: freezing to +65 C
Operating Temperature Range: -10 C to +65 C
Storage Temperature: -40 to +70 C
Water Resistance: Tolerates continuous full immersion
Length: 4.9 inches (12.4 cm)
Diameter: 1.6 inches (4.2 cm)
Weight: 200 g not including cable