Abstract: A synchronizing, pick-off type circuit for use with underground detection systems of a variety utilizing a high voltage pulse generator generating pulses by dielectric breakdown over a gap and evidencing a sustained and discernable substantially lower voltage level for a short interval following the pulse. Pick-off is derived by tapping a transmitting coaxial cable with a "T" connection carrying a choke inductor and a resistor, each of which is coupled to the central conductor of the coaxial cable and which are mutually connected in parallel circuit relationship.

Abstract: An apparatus and method wherein an electrical impulse source transmits a radar-type signal through an antenna into the ground and is reflected by a target. The reflected signal or echo is detected by the antenna and an analog-to-digital converter converts it to a digital form which may be readily operated on, stored and recalled. A memory stores the information until recalled for comparison with a subsequent signal to give an indication of the location of metallic and non-metallic buried targets.

Abstract: An apparatus and method wherein an electrial impulse source transmits a radar-type signal through an antenna into the ground and is reflected by a target. The reflected signal or echo is detected by the antenna and an analog-to-digital converter converts it to a digital form which may be readily operated on, stored and recalled. A memory stores the information until recalled for comparison with a subsequent signal to give an indication of the location of metallic and non-metallic buried targets.

Abstract: An apparatus for detecting the presence of a buried, hidden object in the vicinity of a digging tool in order to prevent a human disaster and damage to utility lines or other buried structures. The apparatus includes an impulse generator and data processing means connected to a slot antenna formed in the tool of an earthmoving machine for radiating a burst of broad spectrum electromagnetic energy into the ground and for receiving and data processing reflected electromagnetic echoes. One antenna embodying the invention comprises a slot formed through a wall of a hydraulically driven shovel and filled with a ceramic absorber. The slot has four radially extending, orthogonally arranged loops having unclosed central portions of the loops joined end to end to form four apexes.

Abstract: An apparatus and method wherein an electrical impulse source transmits a radar-type signal through an antenna into the ground and is reflected by a target. The reflected signal or echo is detected by the antenna and an analog-to-digital converter converts it to a digital form which may be readily operated on, stored and recalled. A memory stores the information until recalled for comparison with a subsequent signal. A processing means compares the stored and subsequent signal to give an indication of the location of metallic and non-metallic buried targets.