Overvoltages on electrical power or telecommunications overhead lines due to nearby lightning strokes can cause faults and disturbances in electrical and electronic devices and apparatuses connected to them. It is important to understand these induced overvoltages, because equipments with electronic devices are sensitive to such disturbances. In this paper, lightning radiated electromagnetic fields caused by the return stroke are evaluated with transmission line engineering models, representing the current through the lightning channel. Integral equations are solved by means the Trapezoidal Rule, resulting in an efficient way to compute the radiated electromagnetic field. Also, the coupling between the electromagnetic field radiated by the return stroke and the overhead line is considered by using The method of characteristics. In this way, transmission line equations to describe voltages and currents in the overhead line are solved in order to compute the induced overvoltages. Results are compared with others internationally published.