The BHG-3 includes three geophone elements, plus a fluxgate compass and a servo mechanism which automatically rotates the horizontal geophones to the azimuth of your choice. The BHGC-1 Controller is available. This unit switches power to the clamp mechanism and compass, and also directs the geophones signal to your standard seismograph. The clamping mechanism is operated by a DC motor, actuated by power sent down two of the conductors. The polarity is reversed to release the clamp. The surface controller provides power to the clamp mechanism and connects the geophone signals to your standard seismic instrument.
The cable is a 7-conductor copperweld with Kevlar® braid and polyurethane jacket, specially manufactured for Geostuff. An SU-8F waterproof connector is molded on the wet end and a Cannon NK-27-21C on the dry end. The cable can be easily disconnected from the geophone for ease of handling. Extension cables are also available with a pair of male and female connectors so that the cable can be temporarily lengthened for unusually deep holes. Popular lengths are normally available from stock, and custom lengths are available on special order. The standard clamp mechanism works for holes between 2 and 6 inches (48-150 mm). Note: to use a 3-axial geophone allow to record shear waves polarized on a horizontal plain.