It was previously shown that when using two powerful transmitters operating on two antenna arrays with a vertical radiation pattern, the phase centers of which are separated by a distance d with a carrier frequency spacing a moving source of low-frequency radiation appears in the lower ionosphere. The phase velocity of such traveling wave antenna coincides with the phase velocity of the main mode of the Earth-ionosphere waveguide at the frequency (F is the carrier frequency difference; h is the height of the ionospheric source above the Earth's surface). At this frequency, a maximum in the radiation amplitude is observed in the experiment. The paper considers a more general case when a HF interferometer operates with an arbitrary angle of inclination of the main beam of both emitters. It is shown that the frequency F strongly depends on the direction of the main beam and can vary over a wide range from units to 15 kilohertz. In this case, it is possible to match the velocity of the current wave in the source with the phase velocity of several first modes of the waveguide. In this case, it is possible to match the current wave of the source with the phase velocity of several first modes of the waveguide. It is shown that the frequency F strongly depends on the direction of the main beam and can vary over a wide range from units to 15 kilohertz. In this case, it is possible to match the velocity of the current wave in the source with the phase velocity of several first modes of the waveguide. We note that so far no experimental verification has been carried out in this formulation, although the technical capabilities of modern heating facilities allow such experiments to be carried out.