Part Numbers

RXW-T11-900RXW-T11-922RXW-T11-868RXW-T11-921

HOBOnet T11 Soil Moisture/Temp Sensor

From $470.00 USD
A durable wireless sensor that works with the HOBOnet system to measure soil moisture (volumetric water content) and soil temperature; lasts up to 10 years in the field.

Important Information

A complete system requires at least one HOBO RX3000 Remote Monitoring Station, a HOBOnet Wireless Manager, and a HOBOnet Wireless Sensor, OR one HOBO MicroRX station (which has an integrated HOBOnet Wireless Manager) and a HOBOnet Wireless Sensor. HOBOnet Wireless Repeaters (RXW-RPTR-xxx or RXW-RPTR-B-xxx) can be added to extend the range.

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Overview

A wireless sensor that works with the HOBOnet system to not only measure soil moisture (volumetric water content) with better accuracy and precision, but also provide soil temperature measurements. Designed to withstand harsh environmental conditions, this durable sensor last up to 10 years, so you can leave them in the field for extended periods of time. Sharpened stainless-steel probes make installation easy, even in hard soil, and an increased volume of influence provides better results and a more accurate view of soil moisture. The HOBOnet T11 is backed by over 20 years of soil-moisture research and features a trademark 70MHz frequency capacitance technology, minimizing salinity and textural effects.

The HOBOnet system is a cost-effective and scalable wireless sensor network for web-enabled monitoring of field conditions for applications such as crop management, research, and greenhouse operations. And because it's wireless, you can deploy a network of sensors to easily monitor multiple points with a single system, while avoiding the risk of long cables that can interfere with field operations and are potentially vulnerable to nearby lightning strikes. Sensors are easily linked to the network, and data can be accessed through HOBOlink®, Onset's innovative cloud software platform.

We suggest using the Verification Clip (see Compatible Items, below). The Verification Clip provides a convenient way to confirm the operation and soil moisture accuracy of HOBOnet T11 and T12 sensors. Attaching this clip to a sensor provides a known soil moisture level for verifying measurement accuracy, without having to test the sensor in actual soils, which normally requires weighing soil samples and drying them in an oven.

Features

Sensor Features

  • Soil moisture (volumetric water content) and soil temperature measurements with one device
  • Sensor lasts up to 10 years in the field
  • Largest volume of influence (1010 mL) relative to sensor size, resulting in more accurate soil moisture measurements
  • Easy installation with sharpened stainless-steel probes that are more resistant to damage/deterioration
  • Less sensor-to-sensor variability

Wireless Features

  • 900 MHz wireless mesh self-healing technology
  • 450 to 600 meter (1,500 to 2,000 feet) wireless range and up to five hops
  • Up to 50 wireless sensors or 336 data channels per HOBO RX station
  • Simple button-push to join the HOBOnet wireless network
  • Onboard memory to ensure no data loss
  • Powered by rechargeable AA batteries and built-in solar panel
Country of Origin
United States

Specifications

Soil Moisture: Volumetric Water Content (VWC)
Measurement Range* 0.00 to 0.70 m³/m³ in mineral soils
Accuracy ±0.030 m³/m³ (±3%) typical from 0 to 50°C (32 to 122°F); ±0.020 m³/m³ (±2%) with soil specific calibration
Resolution 0.001 m³/m³
Dielectric Measurement Frequency 70 MHz
Temperature**
Measurement Range -40 to 60°C (-40 to 140°F)
Accuracy ±1.0°C (1.8°F) from -40 to 0°C (-40 to 32°F)
±0.5°C (0.9°F) from 0 to 60°C (32 to 140°F)
Resolution 0.1°C (0.18°F)
Wireless Mote
Operating Temperature Range Sensor: -40 to 60°C (-40 to 140°F)
Mote: -25° to 60°C (-13° to 140°F) with rechargeable batteries
-40 to 70°C (-40 to 158°F) with lithium batteries
Radio Power 12.6 mW (+11 dBm) non-adjustable
Transmission Range Reliable connection to 457.2 m (1,500 ft) line of sight at 1.8 m (6 ft) high
Reliable connection to 609.6 m (2,000 ft) line of sight at 3 m (10 ft) high
Wireless Data Standard IEEE 802.15.4
Radio Operating Frequencies RXW-T11-900: 904–924 MHz
RXW-T11-868: 866.5 MHz
RXW-T11-921: 921 MHz
RXW-T11-922: 916–924 MHz
Modulation Employed OQPSK (Offset Quadrature Phase Shift Keying)
Data Rate Up to 250 kbps, non-adjustable
Duty Cycle <1%

Maximum Number of Motes

Up to 50 wireless sensors or 336 data channels per one HOBO RX station

Logging Rate 1 minute to 18 hours
Number of Data Channels 3
Battery Type/
Power Source
Two AA 1.2V rechargeable NiMH batteries, powered by built-in solar panel or two AA 1.5 V lithium batteries for operating conditions of -40 to 70°C (-40 to 158°F)
Battery Life With NiMH batteries: Typical 3–5 years when operated in the temperature range -20° to 40°C (-4°F to 104°F) and positioned toward the sun (see Mounting and Positioning the Mote), operation outside this range will reduce the battery service life
With lithium batteries: 1 year, typical use
Memory 16 MB
Dimensions Sensor: 7.47 x 9.4 x 2.39 cm (2.94 x 3.7 x 0.94 inches)
Sensor needle length: 5.4 cm (2.13 inches)
Sensor needle diameter: 0.32 cm (0.13 inches)
Cable length: 5 m (16.4 ft)
Mote: 16.2 x 8.59 x 4.14 cm (6.38 x 3.38 x 1.63 inches)
Weight RXW-T11-xxx sensor and cable: 245 g (8.64 oz)
Mote: 223 g (7.87 oz)
Materials Sensor: ASA plastic body with polyurethane epoxy filling and stainless steel pins
Cable: PVC, UV resistant and rodent repellent
Mote: PCPBT, silicone rubber seal
Environmental Rating Mote: IP67, NEMA 6
Compliance Marks

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FCC Logo

RXW-T11-900

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ce

RXW-T11-868

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Taiwan NCC Mark

RXW-T11-921

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Australia/New Zealand General Compliance mark

RXW-T11-922

* The sensor data can be post-calibrated if necessary (e.g. the sensor is used in non-mineral soil types or higher than standard accuracy is required). Users can apply a calibration equation to the data exported from HOBOlink. The VWC range will depend on the calibration equation.

** Temperature measurement, for applicable sensors, may not be accurate if sensor is not fully immersed in medium of interest, due to longer equilibration time.

Compatible items

Maintenance

TEROS-CLIP
$45.00 USD

Batteries

HWSB-LI
$26.00 USD
HRB-NiMH-2
$12.00 USD

Communications

RXMOD-RXW-xxx
From 190.00
RXMOD-RXW-900
$190.00 USD
RXMOD-RXW-868
$190.00 USD
RXMOD-RXW-922
$190.00 USD
RXMOD-RXW-921
$190.00 USD
RXW-RPTR-xxx
From 150.00
RXW-RPTR-900
$150.00 USD
RXW-RPTR-868
$150.00 USD
RXW-RPTR-922
$150.00 USD
RXW-RPTR-921
$150.00 USD

What's in the box

  • HOBOnet T11 Soil Moisture/Temp Sensor
  • Cable ties
  • Screws

Documents

RXW TEROS-11 Soil Moisture Temp Sensor (RXW-T11-xxx) Quick Start

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RXW TEROS-11 Soil Moisture and Temp Sensor (RXW-T11-xxx) Manual

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TEROS Verification Clip (TEROS-CLIP) Manual

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FAQs

Yes. For shallow installation, an auger may be used to dig to the desired depth. For deeper installations, where manual placement may be difficult, a TEROS Borehole Installation Tool may be purchased or rented from METER Group. This tool enables easy installation up to 1.8 m.

HOBOnet TEROS 11 and TEROS 12 soil moisture sensors come calibrated for most soil types. However, for soil types with high sand or salt content, the standard calibration may not be accurate. In such cases, soil-specific calibration should be used.

To determine the soil-specific calibration formula, please refer to: https://www.onsetcomp.com/support/tech-notes/calibrating-ech2o-soil-moisture-sensors-application-note

Please note too that because the HOBOnet TEROS 21 sensor measures soil water potential, it does not require soil-specific calibration.

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