GPTX 30Wide

HPTX-70 / HPTX-80


The GeoPak HPTX range are High-Power Transmitter (Tx) systems designed for both electromagnetic and galvanic mode geophysical surveys.  Their purpose is to provide a better quality primary signal and consequently allow for high resolution, large scale or deep search geophysical surveys.  Core to its design is provision for safe operation while maximizing efficiency of deployment.


They are capable of output power of up to 70 or 80 kW respectively, and can be used for both time and frequency domain surveys.  It is designed to produce a high amplitude, high quality, precisely timed signal.

  • Powered by a four cylinder turbo charged Deutz diesel engine running at 1800 rpm
  • Can be controlled by Gap GeoPhysics, Zonge and EMIT Tx controllers or internal controller
  • Constant voltage and controlled current modes
  • Can be operated remotely using a PDA and wireless communications
  • Control software allows monitoring and display of all Tx functions.
  • Trailer-mounted designed for applications where vegetation and topography permit vehicle access. 


The HPTX series transmitters have four selectable voltage ranges:

 Operating Ranges



 Range 1

Up to 350A

Up to 360A

 Range 2

Up to 200A

Up to 180A

 Range 3

Up to 100A

Up to 120A

 Range 4

Up to 60A

Up to 60A

These high performance transmitters can be modelled for various loop configurations using GapTxCalc.

The high current output makes these an ideal transmitter for electromagnetic surveys (EM) of all survey configurations including - fixed loop (FLEM), moving loop (MLEM) and downhole (DHEM). The high voltage output also makes it useful for galvanic mode surveys such as - Induced Polarisation (IP), Magnetometric Resistivity (MMR), or Sub-Audio Magnetics (SAM).

Safety Features

  • Fully enclosed all-in-one configuration.
  • Electrical components are protected from the environment.
  • Electrical and mechanical components are inaccessible during operation.  
  • Safety interlocks on all doors.
  • No manual lifting during setup.
  • Reduced trip hazards – all of the cabling is internal apart from the output loop and earth wires.
  • Operating voltage range is generally within the insulation rating of commonly used wire.
  • Circuit breakers – installed on each electrical phase from the alternator
  • Remote operation capability(cable or wireless)
  • Safety beacons
  • Safety guards on moving parts and dummy loads
  • Emergency shutdown
  • Automatic shutdown on error conditions
  • Open circuit protection
  • Internal bunding for the fuel tank
  • Aluminium construction - lightweight
  • Electric brakes with breakaway safety switch.



HPTX Transmitters