Abstract: In a method of identifying a passive electromagnetic signal emitted from an underground utility, a portable above-ground antenna is disposed at a location at which the passive electromagnetic signal is expected. Measurement signals are received from the antenna corresponding to electromagnetic signals received by the antenna. The measurement signals are measured at a plurality of different frequency bands within a measurement frequency range expected to include a frequency of the passive electromagnetic signal, and at least one of the plurality of frequency bands is selected based on a predetermined criteria applied to the measurements.

Abstract: In a method of identifying a passive electromagnetic signal emitted from an underground utility, a portable above-ground antenna is disposed at a location at which the passive electromagnetic signal is expected. Measurement signals are received from the antenna corresponding to electromagnetic signals received by the antenna. The measurement signals are measured at a plurality of different frequency bands within a measurement frequency range expected to include a frequency of the passive electromagnetic signal, and at least one of the plurality of frequency bands is selected based on a predetermined criteria applied to the measurements.

Abstract: A system and method for fault detection including a transmitter adapted to transmit a composite signal on a buried cable so that fault leakage of the composite signal returns to the transmitter through the ground surrounding the buried cable. The composite signal is composed of a low frequency first component that alternates at a first frequency and that defines a phase, and a low frequency second component that alternates at a second frequency higher than the first frequency and that defines a duty cycle having a predetermined relationship with the phase of the first component. A receiver receives the composite signal from the probe and filters the first component, filters the second component, defines an alternating reference signal having a phase based on the duty cycle of the filtered second component, and compares the phase of the reference signal with the phase of the filtered first component.

Abstract: A method for mapping a bore below a ground surface is provided. A boring rod head configured to transmit a signal indicating the pitch angle of the boring rod head with respect to a horizontal plane is disposed within a bore. The boring rod head is advanced within the bore in predetermined linear increments. The pitch angle is measured at each increment. The change in depth is determined at each increment from a prior increment based on the length of the increment and the measured pitch angle at the increment. For each increment, the changes of depth determined in the prior step are added, including the change of depth for the most recent increment. Thus, the depth of the bore at each increment with respect to a predetermined horizontal plane is determined.

Abstract: A system for mapping horizontal bores below a ground surface is provided. A transmitting source radiates a location signal from a bore. The bore may be a newly dug bore or a bore containing an existing utility. A receiver device receives a location signal and indicates, responsively to the location signal, the lateral position of the horizontal bore with respect to the receiver device. A measurement device measures the depth of the bore with respect to the ground surface at selected locations along the bore. A monitor device receives the depth data from the measurement device, compiles the depth data associated with the selected locations with respect to at least one reference position, and outputs the compiled depth data so that the depth of the bore at the selected locations may be collectively identified.

Abstract: Guidance system for an underground boring device that includes a receiver for signals from a signal generator associated with an underground boring head. A wireless transmitter is provided for transmitting the information about the boring head from a boring head location to an initial location where the boring device is controlled.

Abstract: An earth boring apparatus is illustrated including an engine and an earth boring string wherein a hydraulic clutch driven by the engine is supplied with hydraulic fluid through an electrically operated valve controlled by a manually operated trigger so that release of the trigger resulting from a torque as may be occasioned by encountering a rock or other obstruction interrupts manual operation of the trigger disabling the clutch.

Abstract: A guard assembly for encasing drive rods during below ground horizontal drilling is illustrated as including a tube positionable by an adjustable tube guide, which remains stationary during drilling, an expandable tube having a smaller diameter for telescoping into the larger tube, means attaching the smaller tube to the rotary drill power source for substantial encasement of the drive rod during drilling.