What makes these ionospheric heaters so useful is that they consist of phased arrays. A phased array is a grid of antennas whose phases (timing) and amplitudes are individually adjustable. This means a great variety of different combinations can be tried out, synthesizing new and complex total wave forms. Phasing allows the output to be pointed in different directions without having to move the antennas themselves.
For anyone familiar with the works of Tom Bearden, phased arrays also allow for partial phase conjugation or canceling of the emitted electromagnetic waves. When EM waves have either (or both) of their electric and magnetic components cancelled, the contained energy takes the form of a longitudinal / potential / scalar / gravitational / temporal wave instead.
Ionospheric heaters can also “control electron density gradients and the refractive properties in selected regions of the ionosphere” meaning it can modulate ionospheric electron density. That is another powerful method of generating longitudinal waves, using the sky itself as a giant longitudinal antenna.
And so phased arrays can be used to generate an entirely different type of radiation, one that cannot be detected with standard EM-measuring instruments. Depending on their frequency and type, these waves can theoretically affect human emotion and biology, influence the weather, alter tectonic dynamics, and even manipulate our surrounding hyper-dimensional environment to allow for controlled invisibility and interdimensional maneuvering of military personnel and vehicles. In essence, everything that regular electromagnetic waves cannot really do.