EMFAD® UG 12/4 VLF ELECTROMAGNETIC INSTRUMENT

The compact EMFAD® (ElectroMagnetic Field Anomaly Detector) measures variations in VLF radio electromagnetic field data caused by anomalies in the subsoil. It can locate conductive materials, such as metal, pipes, barrels, cables, reinforced concrete, electrolytic effluents, etc. Or irregularities like cavities, graves, faults, shafts, ground fills, deposits, caves, tunnels, and landfills up to a depth of twelve meters.

The EMFAD® VLF technology has been successfully deployed in various climatic and geological conditions by both professionals and amateures. Applications include archeology, geophysics, geology, hydrology, and treasure hunting. Surveyed areas include industrial waste sites and waste deposits, building lots, mining areas, street-construction sites, military practice sites and other soil investigations.

Because the EMFAD® uses the signals from distant VLF radio stations rather than transmitting, it is much smaller and easier to use than typical EM instruments. The EMFAD® is for relativly small targets at a maximum depth of 12 meters (40 feet). The WADI VLF instrument is designed for large targets at a depth up to 100 meters.

Data processing with included software EMFAD-SCAN for 2D and 3D presentations, interpretation, modeling, documentation and printing.

The surveying itself is very simple and can be performed at normal walking speed. First, the area to be measured is marked at its four corners. Then suitable profile lines are laid out to satisfy the requirements of the survey. Larger distances between profiles are first chosen to make overview measurements. Readings can be triggered manually by the operator or once per second in the automatic mode.

If there are abnormal areas shown by the instrument display or by evaluating the data with EMFAD ® -SCAN, the distance between the profiles should be reduced in the area of the anomalies. The selected step-speed and step-distance should be retained for the entire survey.

After taking the measurements for a survey, the EMFAD ® - UG 12/4 can be turned off. The data collected remain in the data logger and can be evaluated and processed with the specialized software EMFAD ® -SCAN at the site or later. The data are transferred to a computer via a serial interface RS-232 or the new, faster USB port.

EMFAD ® - SCAN enables modeling, displaying, and printing the data in 2D- and 3D-views. Complete documentation is provided, and the program is simple to use. After preprocessing with EMFAD ® -SCAN, the data can be further processed in other programs that can import ASCII-files, for example SURFER or MS-EXCEL and others. All requirements for professional reports and presentations can then be met.

Technical Information:
Senses existing VLF electromagnetic transmitters. Does not need its own active transmitter.

Receiver frequency range: 44-142 kHz
Microprocessor controlled measurement
Probe recording: Readings stored 1/s in automatic mode or when triggered in manual mode.
Datalogger: Capacity 16,000 readings
Data point density: Dependent on step-length and distance between measured profiles
Depth of measurement: up to 12 m
Resolution: 10 Bit/5V
Dimensions/Weight: 48x26x10 cm, 2 kg
Power supply: 2 x 9V Batteries (ALKALINE)operating time of approximately 20 hours
Ambient temperature: -20 to 55 C
Data processing: With software EMFAD-SCAN for 2D and 3D presentations, interpretation, modeling, documentation and printing.
Data export: For further processing and display to Microsoft EXCEL, SURFER, or other programs that can read ASCII text files.
Data output/exchange: USB and RS-232 interface.

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