Abstract: The present invention comprises a short-pulse radar guidance tool which determines borehole-to-roof and borehole-to-floor distances along a coal seam by measuring the travel times of electromagnetic pulses transmitted from the tool and reflected back to a receiving antenna in the tool from the interface at the roof or floor of the coal seam. The tool includes a high frequency electromagnetic pulser, a directional transmitting antenna, a directional receiving antenna, a battery power source, and control circuitry for performing all control and transmitting/receiving functions at the tool location. Placement of the transmitting antenna at a point intermediate the control circuitry and the receiving antenna acts to reduce indirect electromagnetic coupling between the antennas. Circuit isolators are used to further attenuate RF crosstalk occuring between the control circuitry and the receiving antenna.