Very low-frequency radio waves can be generated in the lower ionosphere by periodically modulating the conductivity, and thus natural currents, using high power HF radio waves. In conjunction with the heating facility near Troms¿, Norway, such waves have been generated and detected on the ground using two orthogonal receiving antennas so that the polarization ellipse of the VLF signal could be reconstructed. Changes in the strength and direction of the electric field driving the modulated current are reflected in variations in the size and orientation of the VLF ellipse. During a natural Pc 5 pulsation event on October 16, 1981, a close correlation was found between the VLF signal and the electric field pulsations observed by the STARE auroral radars. This first comparison between the Heating and STARE experiments shows that VLF signals from modulated ionospheric heating experiments can provide a sensitive, high time resolution indicator of the ionospheric electric field.