The heating facility at Ramfjordmoen near Troms¿, Norway, has been used to modulate the polar electrojet at frequencies in the range 200--5500 Hz. ELF-VLF signals were received on the ground in the full frequency range, with amplitudes of the order 10 to 100 fT for an effective radiated HF power of 32 MW at 4.04 MHz. A variety of experimental results is presented in this paper.