HOBOnet Multi-Depth Soil Moisture Sensor

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Overview

The HOBOnet Multi-Depth Soil Moisture Sensor is a wireless sensor that works with the HOBOnet system to measure soil moisture and soil temperature at multiple depths with a single probe, for fast and easy installation. This durable sensor is available in three probe lengths for measurements from 45 cm (18 in) to 90 cm (35 in) deep.

Featuring GroPoint’s TDT5 technology with patented antenna design, these sensors measure soil moisture along the entire length of each probe segment, resulting in the largest volume of influence per measurement section. A high frequency of pulses per measurement provides precise and consistent soil moisture data.

We recommend using the optional pilot rod and slide hammer for quick and easy installation. Onset offers two options for the pilot rod, the PILOT-ROD4 (28”) for use with the three- and four-segment sensors (RXW-GP3 and RXW-GP4), and the PILOT-ROD6 (40”) for use with the six-segment sensor (RXW-GP6).

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. Sensors are easily linked to the network, and data can be accessed through HOBOlink®, Onset's innovative cloud-based software platform.

Manufactured by: Onset
Model: HOBOnet Multi-Depth Soil Moisture Sensor

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance

Applications

Soil moisture
Soil temperature

Specification

Soil Moisture: Volumetric Water Content (VWC)
Measurement Range 0.000 to 1.000 m3/m3 in most soils
Accuracy ±0.02 m3/m3 (±2%) in most soils typical from 0° to 50°C (32° to 122°F)*
Resolution 0.001 m3/m3
Temperature
Measurement Range -20° to 70°C (-4° to 158°F)
Accuracy ±0.5°C (0.9°F)
Resolution 0.1°C (0.18°F)
Depths Measured (see below)
RXW-GP3-xxx 45 cm (18 inches) total; three soil moisture zones, six temperature depths
RXW-GP4-xxx 60 cm (24 inches) total; four soil moisture zones, seven temperature depths
RXW-GP6-xxx 90 cm (35 inches) total; six soil moisture zones, eleven temperature depths
Wireless Mote
Operating Temperature Range Sensor: -20° to 70°C (-4° to 158°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-GPx-900: 904–924 MHz
RXW-GPx-868: 866.5 MHz
RXW-GPx-921: 921 MHz
RXW-GPx-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 Maximum logging interval: 18 hours
Recommended minimum logging interval:
    Using Solar Power with Rechargeable Batteries Using Non-Rechargeable Lithium Batteries
  RXW-GP3-xxx: 5 minutes year round 10 minutes
  RXW-GP4-xxx: 5 minutes summer, 10 minutes winter 15 minutes
  RXW-GP6-xxx: 5 minutes summer,
10 minutes winter
15 minutes
Number of Data Channels RXW-GP3-xxx: 10
RXW-GP4-xxx: 12
RXW-GP6-xxx: 18
Battery Type/
Power Source
Two AA 1.2V rechargeable NiMH batteries, powered by built-in solar panel or two AA 1.5 V non-rechargeable 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 non-rechargeable lithium batteries:
RXW-GP3-xxx: 1 year with a 10-minute logging interval
RXW-GP4-xxx: 1 year with a 15-minute logging interval
RXW-GP6-xxx: 7 months with a 15-minute logging interval
Memory 16 MB
Dimensions RXW-GP3-xxx sensor length: 53.2 cm (20.9 inches)
RXW-GP4-xxx sensor length: 68.2 cm (26.9 inches)
RXW-GP6-xxx sensor length: 98.2 cm (38.7 inches)
Sensor diameter: 3 cm (1.2 inches)
Cable length: 3 m (9.8 ft)
Mote: 16.2 x 8.59 x 4.14 cm (6.38 x 3.38 x 1.63 inches)
Weight RXW-GP3-xxx sensor: 351 g (12.4 oz)
RXW-GP4-xxx sensor: 408 g (14.4 oz)
RXW-GP6-xxx sensor: 526 g (18.6 oz)
Cable: 190 g (6.7 oz)
Mote: 223 g (7.87 oz)
Materials Sensor: Polycarbonate housing encasing epoxy sealed circuit board
Cable: Polyurethane
Mote: PCPBT, silicone rubber seal
Environmental Rating Mote: IP67, NEMA 6
*Soil-specific calibration requires user post-processing in a spreadsheet program such as Microsoft® Excel® or a utility and connector as recommend by RioT Technology Corp., manufacturer of GroPoint sensors. Refer to Performing a Soil-Specific Calibration in the manual for details.

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