A Gated, Wideband Magnetic Direction Finder for Lightning Return Strokes

Abstract A magnetic direction finder has been developed which utilizes only the initial few microseconds of wide-band return stroke waveforms to provide accurate directions to the channel bases of lightning discharges to ground. Bearing errors are minimized because, near the ground, most channels tend to be straight and vertical with no large branches or horizontal sections. Tests on a number of lightning storms at distances of 10 to 100 km indicate the angular resolution is in the range from 1° to 2°, with little or no systematic dependence on azimuth or distance.