Directional radar technology is also used in geotechnics to explore areas beyond the face when drifting tunnels. A further directional radar system is available for this purpose. This can be dismantled into short segments, 2 meters long, so that push rods can be used to insert the probe into horizontal boreholes. A mobile winch can also be used to lower them into vertical bores, to depths of up to 1,000 meters.

Surveys of surroundings near the borehole utilise antennae of 50 MHz, 100 MHz and 250 MHz. This apparatus is intended primarily for use in holes drilled horizontally from galleries or tunnels. Measurement is made using a portable control unit. The probe can be inserted by hand into “short holes”, using a push rod. When dealing with “longer measurement stretches”, the probe is attached, using an adapter, to a string of rods and advanced with a drill carriage.
Examples of assignments for which this configuration might be used are exploring active and abandoned workings and identifying geological hindrances in advance of tunnel faces.