Tom Jaski, a noted science writer and engineer duplicated some of Cazzamalli's work with a modern low-power oscillator that was swept from 300 MHz to 600 MHz. His subjects could not see the dial. They were told to sound off as soon as they felt something unusual. The oscillator's output power was only a few milli watts, while the oscillator itself was located several feet away from the subjects.
Milliwatts are quite safe for short term expermiments.