US 4672305 A Electric (E) and magnetic (H) field components of a
lightning stroke are separately received in order to determine
and display the location of regions of recently occuring
lightning activity. Direction is determined by operating upon
electrical signals associated with both the E and H field
components. Range is determined by measuring the magnitude of
the H field at two different frequencies. The range is then
computed as a function of the ratio of the magnitude of the H
field at a first frequency to the magnitude of the H field at a
second frequency. 1. An apparatus for determining the location
of lightning strokes, each lightning stroke generating electric
(E) and magnetic (H) field components, said apparatus
comprising: a. receiving means for receiving separately the
electric (E) and magnetic (H) field components of a lightning
stroke and for generating electrical signals associated with
said E and H field components, said electrical signals being
characterized by an initial rise time and a pl