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.

Sensors can be used with control-, positioning- and support-systems supplied by the user. LED lights indicate the status of power and communication. Sensors receive text commands and provide text output in NMEA-standard (CSV) sentences (or, alternatively, 4-line groups) through their Bluetooth and RS-232 ports. A variety of third-party devices and software can log DUALEM text and integrate it with positions from external GPS receivers.

Sensors are often mounted on a sled or cart, and can be deployed in a watertight housing. A Sensor comes with a data/power cable and manual in a shipping case. Options are (i) a Controller with GPS and (ii) a Harness with data/power module and rectangular feet.

The handheld Controller communicates with its Sensor by Bluetooth and with the internet by Wi-Fi (etc., as provided by the user). It displays data, GPS position and logs positioned data. 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-4) combines a Sensor (e.g. the DUALEM-4S), a Controller and a Harness to form a package convenient for hand-carried surveys.

All DUALEM products can be shipped by popular parcel-express services. Please direct inquiries to Dualem Inc., by contact information listed at www.dualem.com.

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

Pictured: DUALEM-1S sensor in small open sled

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 convenient for towing on a sled or carrying from station-to-station for on-ground measurements. The DUALEM-1S sensor is available separately at lower price for integration with the user’s own surveying systems.

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

Pictured: DUALEM-1H

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 (by the 70-% cumulative-sensitivity guideline), 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. The DUALEM-1HS sensor is available separately at lower price for integration with the user’s own surveying systems.

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. The DUALEM-2S sensor is available separately at lower price for integration with the user’s own surveying systems.

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 3.2-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. The DUALEM-21HS sensor is available separately at lower price for integration with the user’s own surveying systems.

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 6.4 m (by the 70-% cumulative-sensitivity guideline). In-phase measurements sound magnetic susceptibility and detect metal.

4-m DUALEM sensors can be carried by one person with sufficient strength; padding between the sensor and carrier can improve comfort. Alternatively, the harness can be split for 2 people to carry the sensor.

The DUALEM-4S sensor is available separately at lower price for integration with the user’s own surveying systems. Towing on a sled optimizes spatial and geophysical resolution, but a low cart is a typical platform for surveying.

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

The variety of sounding depths makes the DUALEM-421 ideal for the analysis of the thickness, conductivity and susceptibility of layering in the top several metres of the earth.

4-m DUALEM sensors can be carried by one person with sufficient strength; padding between the sensor and carrier can improve comfort. Alternatively, the harness can be split for 2 people to carry the sensor.

The DUALEM-421S sensor is available separately at lower price for integration with the user’s own surveying systems. Towing on a sled optimizes spatial and geophysical resolution, but a low cart is a typical platform 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-642 has dual-geometry receivers at separations of 2-, 4- and 6-m from the transmitter, which provide six simultaneous depths of conductivity sounding, six simultaneous depths of susceptibility sounding, and detection of metal.

The variety of sounding depths makes the DUALEM-642 ideal for the analysis of the thickness, conductivity and susceptibility of layering to 9-m depth. The harness can be used by 2 people to carry the sensor.

The DUALEM-642S sensor is available separately at lower price for integration with the user’s own surveying systems. A low cart is a suitable platform for surveying. The DUALEM-642S disassembles to form a DUALEM-42S or DUALEM-2S.

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

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

The variety of sounding depths makes the DUALEM-842 ideal for the analysis of the thickness, conductivity and susceptibility of layering to 13-m depth. The harness can be used by 2 people to carry the sensor.

The DUALEM-642S sensor is available separately at lower price for integration with the user’s own surveying systems. A low cart is a suitable platform for surveying. The DUALEM-842S disassembles to form a DUALEM-42S or DUALEM-2S.

Controller with GPS and Harness with data/power module

Pictured: Controller and portion of a Harness

The basis of the Controller is the Dualem app. Dualem sells the app preinstalled on an Android smartphone; the Controller also has a weatherproof cover. The preceding picture shows such a Controller. The picture also shows a portion of a Harness with data/power module.

After the purchase of the app for a given sensor, the owner can download the latest version of the Dualem app from Google Play to any suitable Android device for use with that sensor.

An Android device running the Dualem app communicates with the sensor by Bluetooth, and to the internet by Wi-Fi or by other means (e.g. mobile data-service) supplied by the user. The app can display Google Maps (if available) and the survey track, log sensor output with GPS positioning from the device to a comma-separated-values (CSV) file, upload data stored in the memory of the sensor to a CSV file, and upload files to the internet using Gmail (etc.).

The Harness with data/power module features rectangular feet that clamp to the sensor using non-conductive fasteners, a guard and sleeve to protect the cable from the sensor to the data/power module, and the module with (i) a standard 9-socket serial-port connector and (ii) a holder for 8 AA-batteries; the module hangs closely beneath the carrying strap of the harness. Harnesses for 4-m-and-longer sensors also have padded shoulder straps.