Microwave auditory effect

The microwave auditory effect, also known as the microwave hearing effect or the Frey effect, consists of audible clicks (or, with speech modulation, spoken words) induced by pulsed/modulated microwave frequencies. The clicks are generated directly inside the human head without the need of any receiving electronic device. The effect was first reported by persons working in the vicinity of radar transponders during World War II. These induced sounds are not audible to other people nearby. The microwave auditory effect was later discovered to be inducible with shorter-wavelength portions of the electromagnetic spectrum. During the Cold War era, the Americanneuroscientist Allan H. Frey studied this phenomenon and was the first to publish[1] information on the nature of the microwave auditory effect.

Pulsed microwave radiation can be heard by some workers; the irradiated personnel perceive auditory sensations of clicking or buzzing. The cause is thought to be thermoelastic expansion of portions of the auditory apparatus.[2] The auditory system response occurs at least from 200 MHz to at least 3 GHz. In the tests, repetition rate of 50 Hz was used, with pulse width between 10–70 microseconds. The perceived loudness was found to be linked to the peak power density instead of average power density. At 1.245 GHz, the peak power density for perception was below 80 mW/cm2.[citation needed] However, competing theories explain the results of interferometric holography tests differently.[3]

In 2003-2004, the WaveBand Corp. had a contract from the US Navy for the design an MAE system they called MEDUSA (Mob Excess Deterrent Using Silent Audio) intended to remotely, temporarily incapacitate personnel. The project was cancelled in 2005.[4][5][6]

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The first American to publish on the microwave hearing effect was Allan H. Frey, in 1961. In his experiments, the subjects were discovered to be able to hear appropriately pulsed microwave radiation, from a distance of 100 meters from the transmitter. This was accompanied by side effects such as dizziness, headaches, and a pins and needles sensation.

A decade later, an overview, in the American Psychologist, of radiation impacts on human perceptions, cites investigations at the Walter Reed Army Institute of Research that demonstrated 'receiverless' wireless voice transmission: "Appropriate modulation of microwave energy can result in direct 'wireless' and 'receiverless' communication of speech."[7]

A 1998 patent describes a device that can scare off birds from wind turbines, aircraft, and other sensitive installations by way of microwave energy pulses. Using frequencies from 1 GHz to about 40 GHz, the warning system generates pulses of milliseconds duration, which are claimed to be sensed by the birds' auditory systems. It is believed this may cause them to veer away from the protected object.[8]

As stated by the above-mentioned journal entry to the American Psychologist, "the averaged densities of energy required to transmit longer messages would approach the current 10mW/cm² limit of safe exposure", which makes the technology improper for human telecommunication. For this very same 'receiverless' wireless sound transmission to human beings, sound from ultrasound is used instead.

There are extensive online support networks and numerous websites maintained by people fearing mind control. California psychiatrist Alan Drucker has identified evidence of delusional disorders on many of these websites[9] and other psychologists are divided over whether such sites negatively reinforce mental troubles or act as a form of group cognitive therapy.[11]