A different transmitter Frey used measured 71 w/m² at 425 MHz, with peaks at 2540 w/m².
Compare this to the FCC guideline of 2 w/m² at that frequency.
The leading theory is pulsed RF energy heats the tissues of the inner ear, causing them to expand quickly.
These expansions cause tiny shockwaves which are then interpreted as sounds by the brain.
What exactly causes the RF energy to be converted to sound?