The G-824A Magnetometer has an ultra-high sensitivity of 500 fT/√Hz RMS sensitivity and ultra high sample rates up to 1000 Hz. The Geometrics G-824A combines high-performance and well-proven cesium sensor with new a sensitive internal sensor driver and Larmor counter electronics. Improved low noise amplifiers have now lowered the noise floor to approximately 500 fT (femto-Telsa). This advanced integrated magnetometer provides unmatched versatility in performance, small size, low weight, wide application range and cost effectiveness. The system's high performance and multi-function capability are excellent for mapping geologic structure for mineral and gas exploration. Rapid sample rates enhance the detection and delineation of targets for environmental, archaeological or UXO and EOD surveys. Detection ranges, classification and precision mapping are improved by the G-824A performance and in some cases provide results not achievable by any other means. The G-824A meets the highest standards for airborne, land or marine surveys meeting rigorous vibration and environmental testing standards. Gradiometer sensor arrays are particularly effective for geologic mapping and search. The G-824A provides the ability to concatenate RS-232 outputs from up to 8 sensor/counter assemblies into a single digital stream, transmitted up a single cable and record on a single computer serial port. Each of these sensors is synchronized to within 1ms for simultaneous measurement and true gradient measurements.

Features and benefits

  • Extreme Sensitivity and Speed: 500 fT/√Hz RMS and 1000 Hz with internal counter.
  • Very Low Heading Error: ±0.15nT over 360˚equatorial and polar spins. Systems supplied with spin curves for gradiometer installation curve matching.
  • Versatility: includes 6 channel 12 bit A/D converters for digitization of altimeter or other analog signals, digital data stream concatenation, telemetry option, wide voltage range.
  • Reliability and Ruggedness: Cesium magnetometers never need be returned to factory for calibration or tuning. Design for tough environmental conditions and high "G" loads.
  • Gradiometer arrays offering simultaneous operation of up to eight separate sensors using the designed-in serial port concatenation capability.
  • Geometrics offers complete turnkey systems including birds, stingers, wingtip installation accessories as well as digital data acquisition systems, post acquisition Magnetic Compensation software, Flight path recovery cameras, GPS navigation, gamma ray spectrometers and post acquisition data processing software and training.

Technical Details

G-824A Magnetometer Specification List

G-824A Magnetometer

    • Operating Principle: Self-oscillating split-beam Cesium Vapor (non-radioactive)
    • Operating Range: 20,000 to 100,000 nT
    • Operating Zones: The earth’s field vector should be at an angle greater than 10° from the sensor’s equator and greater than 10° away from the sensor’s long axis. Automatic hemisphere switching.
    • Sensitivity:500 fT/√Hz rms NOTE: US EXPORT LICENSE REQUIRED.
    • Max Sample Rate: 1000 Hz.
    • Heading Error: ± 0.15 nT (over entire 360° polar and equatorial spin). Not specified on G-824B.
    • Output: RS-232 data at 115K baud, concatenated data streams from up to 8 sensors depending on sample rate, compressed binary.
    • Power: 24 to 32 VDC, 2.0 amp at power-on and 1.0 amp thereafter.
    • Gradient Tolerance: 500 nT/in.
    • Temperature Drift: <0.05 nT/°C


  • Total Weight: (including interconnect cable) 2.7Kg (5.9 lb).
  • Sensor (cylindrical): L: 6 cm; W: 15.6 cm (2.375x6.125 in).
  • Electronics (rectangular): L: 6.35 cm; W: 38 cm; 8.9 cm diagonal corners (2.5x15x3.5 in).
  • Electronic Base Plate: L: 6.35 cm; W: 40.6 cm (2.5x16 in)
  • Base Plate Mounting Holes: DIA: 0.635 cm (0.25 in).
  • Cables:
  • Sensor to electronics: Standard 2.77 m (9 ft) with connector on electronics end. Other lengths available from 0.75 m to 3.75 m (2.4 ft to 12.75 ft) at 1 m (40-in) increments. Lengths approximate due to cable variations.
  • Power, Data, & Signal: RS-232 to Computer, standard 8 m, 60 m max (26.26 ft, 196.85 ft max).


  • Operating Temperature: -30°F to +122°F (-35°C to +50°C)
  • Storage Temperature: -48°F to +158°F (-45°C to +70°C)
  • Altitude: Up to 30,000 ft. (9,000 m)
  • Weatherproof: O-Ring sealed for operation in 100% humidity.


  • Standard: Power/RS-232 multi-conductor cable (electronics to power/data junction box with 9 pin RS-232 connector and power lugs), lengths to be specified, spare O-Rings, operation manual and carrying case.
  • Optional:
  • Logging Software: MagLog (Logs GPS and Mag, shows track plot, mag profile, other data).
  • Accessories: Birds, Stingers, Wingtips, Avionics, GPS, Gamma Ray, Logging Computer

    Other Models

  • G-824B: Geometrics, Inc. also provides G-824 systems for stationary mounted configurations that can address surveillance and other remote detection applications. These systems are identical in all performance and reliability standards except heading error. These “B” systems are offered for land or marine base station use. The G-824B system comes complete with interconnect cables, power/data junction box, power supply and optional tripod assembly.
G-824A Magnetometer Shipping Weights & DIMS

Shipping Weights & DIMS

Contents Dimensions (L x W x H) Weight
Case 1 - G-824A Magnetometer 20in x 20in x 21in 51cm x 51cm x 53cm 30lbs 14kg


  • In-Accessible Terrain: Difficult or dangerous terrain is no longer a problem, making it perfect for surveying wetlands, heavily vegetated areas, extreme terrain, or protected lands.
  • Environmental: Find abandoned wells, pipes, and storage tanks quickly and with precise positioning.
  • Archaeology: Survey vast distances and leave potential archaeology sites undisturbed from the air.
  • Geology: Survey for regional variations in the magnetic field.
  • UXO Detection: Collect data at high speed with a fast sample rate, making detection and delineation of UXO quick and easy.