Microwave auditory effect - Wikipedia

Microwave auditory effect - Wikipedia: Allan%20H.%20Frey%20was%20the%20first%20American%20to%20publish%20on%20the%20microwave%20auditory%20effect%20%28MAE%29.%20Frey%27s%20%22Human%20auditory%20system%20response%20to%20modulated%20electromagnetic%20energy%22%20appeared%20in%20the%20Journal%20of%20Applied%20Physiology%20in%201961.%5B1%5D%20In%20his%20experiments%2C%20the%20subjects%20were%20discovered%20to%20be%20able%20to%20hear%20appropriately%20pulsed%20microwave%20radiation%2C%20from%20a%20distance%20of%20a%20few%20inches%20to%20hundreds%20of%20feet%20from%20the%20transmitter.%20In%20Frey%27s%20tests%2C%20a%20repetition%20rate%20of%2050%A0Hz%20was%20used%2C%20with%20pulse%20width%20between%2010%u201370%20microseconds.%20The%20perceived%20loudness%20was%20found%20to%20be%20linked%20to%20the%20peak%20power%20density%2C%20instead%20of%20average%20power%20density.%20At%201.245%A0GHz%2C%20the%20peak%20power%20density%20for%20perception%20was%20below%2080%A0mW/cm2.%20According%20to%20Frey%2C%20the%20induced%20sounds%20were%20described%20as%20%22a%20buzz%2C%20clicking%2C%20hiss%2C%20or%20knocking%2C%20depending%20on%20several%20transmitter%20parameters%2C%20i.e.%2C%20pulse%20width%20and%20pulse-repetition%20rate%22.%20By%20changing%20transmitter%20parameters%2C%20Frey%20was%20able%20to%20induce%20the%20%22perception%20of%20severe%20buffeting%20of%20the%20head%2C%20without%20such%20apparent%20vestibular%20symptoms%20as%20dizziness%20or%20nausea%22.%20Other%20transmitter%20parameters%20induced%20a%20pins%20and%20needles%20sensation.%20Frey%20experimented%20with%20nerve-deaf%20subjects%2C%20and%20speculated%20that%20the%20human%20detecting%20mechanism%20was%20in%20the%20cochlea%2C%20but%20at%20the%20time%20of%20the%20experiment%20the%20results%20were%20inconclusive%20due%20to%20factors%20such%20as%20tinnitus.%5B1%5D%5B5%5D%0A%0AAuditory%20sensations%20of%20clicking%20or%20buzzing%20have%20been%20reported%20by%20some%20workers%20at%20modern-day%20microwave%20transmitting%20sites%20that%20emit%20pulsed%20microwave%20radiation.%20Auditory%20responses%20to%20transmitted%20frequencies%20from%20approximately%20200%A0MHz%20to%20at%20least%203%A0GHz%20have%20been%20reported.%20The%20cause%20is%20thought%20to%20be%20thermoelastic%20expansion%20of%20portions%20of%20auditory%20apparatus%2C%20and%20the%20generally%20accepted%20mechanism%20is%20rapid%20%28but%20minuscule%2C%20in%20the%20range%20of%2010%u22125%20%B0C%29%20heating%20of%20brain%20by%20each%20pulse%2C%20and%20the%20resulting%20pressure%20wave%20traveling%20through%20the%20skull%20to%20the%20cochlea.%5B5%5D%0A%0AIn%201975%2C%20an%20article%20by%20neuropsychologist%20Don%20Justesen%20discussing%20radiation%20effects%20on%20human%20perception%20referred%20to%20an%20experiment%20by%20Joseph%20C.%20Sharp%20and%20Mark%20Grove%20at%20the%20Walter%20Reed%20Army%20Institute%20of%20Research%20during%20which%20Sharp%20and%20Grove%20reportedly%20were%20able%20to%20recognize%20nine%20out%20of%20ten%20words%20transmitted%20by%20%22voice%20modulated%20microwaves%22.%20Since%20the%20radiation%20levels%20approached%20the%20%28then%20current%29%2010%A0mW/cm%B2%20limit%20of%20safe%20exposure%2C%20critics%20have%20observed%20that%20under%20such%20conditions%20brain%20damage%20from%20thermal%20effects%20of%20high%20power%20microwave%20radiation%20would%20occur%2C%20and%20there%20was%20%22no%20conclusive%20evidence%20for%20MAE%20at%20lower%20energy%20densities%22.%5B6%5D%5B7%5D%0A%0A