Products

DUALEM Products

A DUALEM sensor (Sensor) incorporates one-, two- or three-sets of the patented DUALEM dual-geometry array. Each dual-geometry array simultaneously measures both electrical conductivity and magnetic susceptibility to two distinct and defined depths. Multiple sets of arrays enable the estimation of the distribution of these properties in a layered earth.

A Sensor has an internal logger that records electromagnetic (EM) responses, grid coordinates, time, temperature, power voltage, X-Y-Z components of acceleration and the ambient magnetic field, pitch and roll. Most Sensors have the option for an internal GPS receiver; if there is a GPS fix for a Sensor with GPS, its internal logger also records NMEA $GPGGA sentences.

Sensors operate by EM induction into the earth (i.e. not by galvanic contact with the ground). This enables surveying at moderate speed over rough, non-conductive terrain, such as bedrock, pavement, stones, desiccated soil, dense vegetation and ice.

Sensors are calibrated precisely at the factory using a patented technique, eliminating the limitations of ad hoc calibrations in the field. Precise calibration, base-level stability, high sensitivity and advanced digital signal processing give the Sensors unmatched accuracy.

LED lights indicate the status of power and communication. Sensors receive text commands and provide text output in NMEA-standard (CSV) sentences (or, alternatively, concise packets of text) through their Bluetooth and RS-232 ports. A variety of third-party devices and software can log DUALEM output
and integrate it with positions from external GPS receivers.

A Sensor comes with a data/power cable and manual in a shipping case. Sensors are often mounted on a sled or cart, and can be deployed in a watertight housing.

Dualem sells Sensors for integration with control-, positioning- and support-systems supplied by the user. Dualem also sells a Controller with GPS and a Harness with data/power module and rectangular feet. A Sensor with both of these options can be hand-carried on survey, and provides positioned measurements that can be uploaded conveniently to the internet for further processing and display.

The Controller is an Android smartphone running the DUALEM app. It communicates with its Sensor by Bluetooth. It displays sensor output, GPS position on Google Maps and logs positioned data. It uploads logged data to the internet, e.g. by e-mail through Wi-fi, as arranged by the user. It has a weatherproof cover, and can receive supplementary power through its micro-USB port.

The Harness facilitates carrying the Sensor for walking-speed surveys, and its rectangular feet help with alignment in station-by-station surveys. Its data/power module has a 9-socket connector for RS-232 communication and a holder for 8-AA batteries to power the Sensor.

A DUALEM instrument (e.g. the DUALEM-421) combines a Sensor (e.g. the DUALEM-421S), a Controller and a Harness.

All DUALEM products can be shipped by popular parcel-express services.

DUALEM-1 (DUALEM-1S, Controller and Harness)

Pictured: DUALEM-1S sensor with Harness

The DUALEM-1 has 1-m separation between its transmitter and dual receivers, so its dual depths of conductivity measurement are 0.5 m and 1.6 m (by the 70-% cumulative-sensitivity guideline).  In-phase measurements sound magnetic susceptibility and detect metal.

The DUALEM-1 depths of measurement are ideal for many agricultural applications, and spatial resolution that is well suited to archaeological investigation.  For metal detection, the DUALEM-1 can detect a steel drum to a depth of about 1 m.

The compact size of the DUALEM-1 makes it ideal for towing on a sled or carrying from station-to-station for on-ground measurements.

DUALEM-1H (DUALEM-1HS, Controller and Harness)

The DUALEM-1H has dual-geometry receivers at separations of 1- and ½-m from the transmitter, which provide simultaneous 0.3-, 0.5-, 0.8- and 1.6-m depths of conductivity sounding, four simultaneous in-phase (susceptibility) measurements, and metal detection.

The multiple sounding-depths of the DUALEM-1H enable the analysis of layering in the top 2-m of the earth.

The depth range and spatial resolution of the DUALEM-1H are ideal for many agricultural and archaeological applications. The compact size of the DUALEM-1H makes it convenient for towing on a sled or carrying from station-to-station for on-ground measurements.

DUALEM-2 (DUALEM-2S, Controller and Harness)

Pictured: An “old-style” DUALEM-2 on hand-carried survey in the Mojave Desert

The DUALEM-2 has 2-m separation between its transmitter and dual receivers, so its dual depths of conductivity measurement are 1 m and 3 m. In-phase measurements sound magnetic susceptibility and detect metal.

The DUALEM-2 depths of measurements are well suited to a variety of applications in agriculture and surficial mapping.  For metal detection, the DUALEM-2 can detect a steel drum a depth of about 2 m.

The shoulder-harness, smooth tubular design and moderate weight make the DUALEM-2 practical for prolonged surveys by a single operator.  The DUALEM-2 is also convenient to pull on a sled at the ground surface to maximize sensitivity and spatial resolution.

DUALEM-21 and DUALEM-21S

Pictured: A DUALEM-21S enclosed in an articulated sled with GPS by Universitet Aarhus

The DUALEM-21 has dual-geometry receivers at separations of 2- and 1-m from the transmitter, which provide simultaneous 0.5-, 0.1-, 1.6- and 3-m depths of conductivity sounding, four simultaneous in-phase (susceptibility) measurements, and metal detection.

The several sounding-depths of the DUALEM-21 enable the analysis of layering in the top few metres of the earth.

The DUALEM-21 can be carried on prolonged surveys by a single operator, and is suitable for towing on a sled or low cart.

DUALEM-21H (DUALEM-21HS, Controller and Harness)

The DUALEM-21H has dual-geometry receivers at separations of 2-, 1- and ½-m from the transmitter, which provide simultaneous 0.3-, 0.5-, 0.8-, 1-, 1.6- and 3-m depths of conductivity sounding, six simultaneous in-phase (susceptibility) measurements, and metal detection.

The multiple sounding-depths of the DUALEM-21H enable the analysis of layering in the top 4-m of the earth.

The DUALEM-21H can be carried on prolonged surveys by a single operator, and is suitable for towing on a sled or low cart.

DUALEM-4 (DUALEM-4, Controller and Harness)

Pictured: DUALEM-4S on a cart with solid wheels and GPS

The DUALEM-4 has 4-m separation between its transmitter and dual receivers, so its dual depths of conductivity measurement are 2 m and 6 m.

The DUALEM-4 depths of measurements are well suited to a variety of applications in agriculture, geotechnics and hydrology.  For metal detection, the DUALEM-4 can detect a steel drum to a depth of about 3 m.

The double shoulder-harness and smooth tubular design make the DUALEM-4 practical for surveys by a single operator.  Many users pull the DUALEM-4S on a cart behind a motor vehicle.

DUALEM-42 (DUALEM-42S, Controller and Harness)

The DUALEM-42 has dual-geometry receivers at separations of 4- and 2-m from the transmitter, which provide simultaneous 1-, 2-, 3- and 6-m depths of conductivity sounding, four simultaneous depths of susceptibility sounding, and detection of metal.

The several sounding-depths of the DUALEM-42 enable the analysis of layering in the top several metres of the earth.  The DUALEM-42 is suitable for towing on a sled or cart, or for carrying at hip height.  The DUALEM-42S disassembles to form a DUALEM-2S, for more convenient surveys of shallower targets.

DUALEM-421 (DUALEM-421S, Controller and Harness)

Pictured: A DUALEM-421S on a simple raft

The DUALEM-421S has dual-geometry receivers at separations of 4-, 2- and 1-m from the transmitter, which provide simultaneous 0.5-, 1-, 1.6- 2-, 3- and 6-m depths of conductivity sounding, six simultaneous depths of susceptibility sounding, and detection of metal.

The variety of sounding depths makes the DUALEM-421S ideal for the analysis of the thickness, conductivity and susceptibility of layering in the top several metres of the earth.    Towing on a sled optimizes spatial and geophysical resolution, but a low cart and hand-carrying by 2 people are also suitable platforms for surveying.  The DUALEM-421S disassembles to form a DUALEM-21S.

DUALEM-642 (DUALEM-642S, Controller and Harness)

Pictured: A DUALEM-642S carried with split Harness

The DUALEM-642S has dual-geometry receivers at separations of 6-, 4- and 2-m from the transmitter, which provide simultaneous 1-, 2-, 3-, 3.2-, 6- and 10-m depths of conductivity sounding, six simultaneous depths of susceptibility sounding, and detection of metal.

The variety of sounding depths makes the DUALEM-642S effective for the analysis of the thickness, conductivity and susceptibility of layering in the top decametre of the earth. A low cart is the usual platform for surveying, and for smaller surveys the DUALEM-642 can be hand-carried by 2 people. The DUALEM-642S disassembles to form a DUALEM-42S, and a DUALEM-2S.

DUALEM-842 (DUALEM-642S, Controller and Harness)

The DUALEM-842S has dual-geometry receivers at separations of 8-, 4- and 2-m from the transmitter, which provide simultaneous 1-, 2-, 3-, 4, 6- and 13-m depths of conductivity sounding, six simultaneous depths of susceptibility sounding, and detection of metal.

The variety of sounding depths makes the DUALEM-642S ideal for the analysis of the thickness, conductivity and susceptibility of layering in and beyond the top decametre of the earth. A low cart that provides structural support to the sensor is the usual platform for surveying, and for smaller surveys the DUALEM-842 can be hand-carried by 2 people. The DUALEM-842S disassembles to form a DUALEM-42S, and a DUALEM-2S.