Dualem

DUALEM instruments measure the conductivity and magnetic susceptibility of the ground for soil profiling and can also be used to find buried metal.  The patented DUALEM dual-geometry array simultaneously measures conductivity and susceptibility to two distinct and easily quantified depths.
 
DUALEM instruments are calibrated precisely and permanently at the factory using a patented technique, eliminating problematic ad hoc calibrations in the field.  Precise calibration, base-level stability, high sensitivity and advanced digital signal processing give the instruments unmatched accuracy.
 
DUALEM instruments provide output to their RS-232B port in either NMEA0183-standard or DUALEM format.  As NMEA0183 is the standard for GPS communication, a wide variety of GPS loggers and software can record DUALEM measurements and integrate them with GPS positions.
 
DUALEM instruments operate by electromagnetic induction, so no contact with the ground is needed, which enables surveying at moderate speed over uneven or electrically resistive terrain.  Terrain that has been surveyed using DUALEM instruments includes forests, recent volcanic flows, and multi-year ice.

Depending on your application, Dualem instruments are available on 1, 2 and 4 meter booms.  They can also have multiple separations enabling a complete soil profile to be captured in 1 pass.  For example a Dualem-421S measures conductive at 0.5m, 1m, 1.5m, 2m, 3m and 6m in one pass.

DUALEM-2 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 (by the 70-% cumulative-sensitivity standard).  For metal detection, the DUALEM-2 can detect a steel drum to 2-m depth.   The double 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-4 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 (by the 70-% cumulative-sensitivity standard).  For metal detection, the DUALEM-4 can detect a steel drum to depths greater than 3 m. The double shoulder-harness and smooth tubular design make the DUALEM-4 practical for surveys by a single operator.  Some users pull the DUALEM-4 on a cart behind a motor vehicle.