terraTEM24 Specifications


  • Number of input channels: Offered with 1,2 3, 6 or 9 simultaneously recorded channels. Systems with 12 channels are also available upon request.
  • Resolution: True 24 bit resolution per sample. Resolution depends on the gain setting which can be either manual or automatic. Minimum single point resolution is 23 nV.
  • Input Range:  Maximum measurable input voltage is +/- 200V. All channels fitted with 700 V input protection.
  • Sampling rate:  User-selectable from 78 kHz to 625 kHz at full 24bits for each sample. Each channel has a distinct signal path and ADC and to minimise cross coupling. All data channels are simultaneously sampled.
  • Windows (gates): 200 windows maximum. Pre-defined and user-selectable windowing schemes available. Along with windowed data, full waveform data can also be saved allowing soundings to be processed post-survey. This allows the user to change the window scheme, adjust delays for different external transmitters and receivers.
  • Functions measured: Tx turn on and turn off times, loop input voltage, Tx and where applicable Rx loop resistances, full transmitter current waveform, transient response, and many more parameters. Noise measurements can be acquired with the same parameters as a sounding to allow a direct comparison. Spectral analysis and oscilloscope modes are also available.
  • Stacking options: 1 to 65,536 stacks.
  • Gain: 1 to 100 and an auto gain option. With 24 bits there is no requirement for higher gains. A 0.1 gain is available for using with coincident or single loop configurations.


  • Output current:  50 A at 6 V through to 120 V (6kW) internal transmitter as standard. An optional external transmitter, the terraTX-50 (50 A 250 V) is also available. Both these transmitter configurations can be operated from batteries or the Monex GeoScope Voltage Rectifier. Synchronisation between the terraTEM24 receiver and the optional external transmitter (terraTX-50) is via cable or GPS. An optional crystal module synchronisation is also available. Synchronisation with the internal transmitter is built into the hardware.
  • Waveform:  Bipolar waveform with 50% duty cycle.
  • On/off time:  Adjustable from 10 to 2,000 ms on/off time.
  • Turn off:  Depends on the selected transmitter. For example a terraTX-50, 10 Amp for 50 m x 50 m, 7.2 microseconds.  50 Amp for 50 m x 50 m, 36 microseconds. 33 Amp for 100 m x 100 m, 48 microseconds. The user can also increase the ramp length from the minimum required.
  • Transmitter repetition rate:  25 Hz to 0.125 Hz or 40 milliseconds to 8 seconds.
  • Transmitter loop size (effective area):  This is dependent upon the client’s own survey specifications. The transmitter can operate on any loop size/configuration.
  • Moments:  User-selectable moments are available with the optional rectifier, allowing the input loop power to be adjusted rather than using external load power resistors. The user can accurately adjust the transmitter current to any value less than the 50 A maximum. This can either be controlled by the terraTEM24 receiver or directly by the operator.


  • Display: 10″ colour capacitive touchscreen, daylight visible with 800 x 600 resolution.
  • Storage: 30 GByte memory with soundings saved as standard stacked and windowed along with the full waveform if required.
  • I/O port: Data transfer is via USB. External GPS connectivity is via a serial port. All receiver ports are fitted with individual RS485 ports foc communicating with active sensors.
  • Software: The data reduction and processing package allows for data quality control, contouring, apparent conductivity pseudosections, contouring of gridded data and data editing. Stacked and binned response curves, stacked waveforms with optional full time-series data saving, signal averaging algorithms, digital signal processing, sferic rejection and spectral analysis are all available. Data can be viewed in various formats depending upon user preferences. Profile and decay plotting capabilities are also included for in-field data review and quality control. Optional 1D inversion software is also available.
  • Operating temperature:  -20°Celsius to +50°Celsius.
  • Housing:  Rugged aluminium case.
  • Case dimensions: 46 cm × 36 cm × 16 cm, 10 kg.
  • Carry case:  Sturdy field transit case provided.
  • Manual:  A comprehensive operation and trouble shooting manual is provided in soft copy form.
  • Battery charger:  Suitable battery charger provided.
  • Warranty:  One year.


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