The BHG Gradiometer Magnetic Locator from SubSurface Instruments detects underground ferrous metals at a radius of ±8 feet. It can also be used underwater. It has two titanium-housed sensors that function as magnetic locators and can easily be lowered into boring holes. Its sensitivity, accuracy, and durability make it ideal for utility companies and construction use. This package includes the primary control electronic box, BHG sensor, and connectivity cables. Sensor cables (30’, 50’, 100’) are sold separately.
How it works: The Bore Hole Gradiometer (BHG) is a magnetic gradiometer that locates objects by detecting differences in magnetic field strengths using the two sensors inside the sensor tube housing. This difference is measured in “Differential Milligauss.” You will be notified of the signal reading using a bar graph on the LCD screen and audio signals (via speaker or headset). The bar graph fills to the left (negative) or right (positive) depending on the signal polarity—also, the audio pitch increases as the signal strength increases.
Control box: Aside from the LCD screen, the electronic control box has a control panel with buttons for powering the device on/off, adjusting the volume and gain, and more. It also has an RS-232 port to enable control using a computer, a sensor port for connecting the box to the MUL sensor, and a power port for running the device on external power. The rechargeable battery is built into the control box.
Sensor: The BHG sensor is highly sensitive to the presence of buried metals such as drums or ordnance. It is bull-nosed, tapered, and measures 1.625” D x 17.5” L.