Sanborn’s TDEM System.

Helicopter Borne Time Domain EM System


  • Powerful compact transmitter
  • Three component receiver (x,y,z)
  • Lightweight and rigid frame
  • Easy operation and mob in rough terrain
  • Scalable to a wide range of helicopters
  • Easy helipad and hangar storage
  • Easy assembly and installation
  • Small loop footprint
  • Improved spatial resolution
  • Full wave-form recorded data
  • User Selected Programmable windows

Key Figures.

1400 A Peak Current

325000 NIA Peak Dipole Movement

400 + m Estimated Depth Penetration

Technical Specification.

Transmitter (Tx) Rigid, Aluminum tubes
Tx Coil Vertical axis
TC Coil Diameter 8.6m
Number of Turns 4
Pulse Shape Half-sine
Pulse Length Approx. 4ms for 25/30 Hz: 1.5ms for 75/90 Hz
Base Frequency 25 or 30 Hz
Optional base frequency 75 or 90 Hz
Peak Current 1,400 A
Peak Dipole movement 325,000 NIA
Estimated penetration 400 + m
Power Supply Independent on loop
System suspension one tow rope, single point suspension
Tx elevation over ground 30m
Weight 350 Kg (configuration dependant)
Helicopter type AS350 Series preferred
Survey Speed 90 Km/h – standard
Receiver (Rx) X, Y, Z
Position of Receiver Mid-tow rope, asymmetrical
Rx elevation over the ground 60m (for standard setup)
dB/dt Yes
B-field Yes
Data Extraction (programmable windows),
QC and processing
Done in post processing immediately after each flight
Data recording Full wave form recording
Sample rate 90kHz
Data resolution 11 μS/sample @ 30 Hz base frequency
Industrial noise rejection 60 or 50 Hz, cancelling
Additional Tx info Tx Current monitor channel
Tx pulse control Yes
Sensors on Tx loop GPS, Laser Altimeter
Rigid system Designed to operate in flat or rugged terrain
Installation time 2-4 hrs; 2 persons

Specification Highlights.

  • Has semi-sinusoidal shape transmitter pulse
  • Transmitter frequency can be adjusted to 25Hz or 75Hz in a 50Hz environment; 30Hz or 90Hz in a 60Hz environment
  • Records the raw data coming from an XYZ receiver and a transmitter current monitor continuously (ON-time and OFF-time)
  • Recorded Raw data can be converted to windows (time channels) of any times and width, according to geological requirements
Sanborn's TDEM System

EM Data View.

The EM Data Extraction and visualization program allows the user to perform post-mission data processing and extraction, including noise-reduction, data recalculation, and extraction of time-channels.

Key Features.

  • Windows-based platform
  • Data analysis and QC
  • Pulse shape export
  • External noise suppression
  • Advanced de-noising algorithm
  • Flexibility in time-channels extraction
  • Output data sets can be imported into Oasis Montaj; EM Flow
  • Maxwell or other processing and interpretation software
EM Data View

Explore more with Sanborn.

Download the TDEM System Specification as PDF, or contact our sales team who are standing by ready to guide you.