Shield against induction of sounds from remote source of RF

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SUMMARY

The discussion centers on the phenomenon of inducing sound perception in humans through electromagnetic waves, as detailed in the Journal of Applied Physiology. It highlights that sounds can be perceived at distances of several hundred feet from the transmitter, with critical factors including peak power density and carrier frequency. A peak power density of approximately 275 mW/cm² is necessary to induce sound perception in the presence of 80 dB acoustic noise. The conversation also addresses practical shielding methods, noting that while a metal plate offers some attenuation, a Faraday Cage provides complete isolation without altering the frequency of the waves.

PREREQUISITES
  • Understanding of electromagnetic energy and its interaction with human perception
  • Familiarity with concepts of power density and its measurement
  • Knowledge of acoustic energy and sound perception mechanisms
  • Basic principles of electromagnetic shielding, including Faraday Cages
NEXT STEPS
  • Research the principles of electromagnetic wave modulation and its effects on sound perception
  • Explore the design and effectiveness of Faraday Cages for electromagnetic shielding
  • Investigate the relationship between power density and sound induction in various environments
  • Study the physiological mechanisms of sound perception in response to electromagnetic stimuli
USEFUL FOR

Physiologists, audio engineers, researchers in electromagnetic fields, and professionals involved in sound perception studies will benefit from this discussion.

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It has been demonstrated that it is possible to make humans hear sounds using waves.

Abstract From Journal of Applied Physiology
The intent of this paper is to bring a new phenomenon to the attention of physiologists. Using extremely low average power densities of electromagnetic energy, the perception of sounds was induced in normal and deaf humans. The effect was induced several hundred feet from the antenna the instant the transmitter was turned on, and is a function of carrier frequency and modulation. Attempts were made to match the sounds induced by electromagnetic energy and acoustic energy. The closest match occurred when the acoustic amplifier was driven by the rf transmitter's modulator. Peak power density is a critical factor and, with acoustic noise of approximately 80 db, a peak power density of approximately 275 mw/ cm2 is needed to induce the perception at carrier frequencies of 425 mc and 1,310 mc. The average power density can be at least as low as 400 μw/cm2. The evidence for the various possible sites of the electromagnetic energy sensor are discussed and locations peripheral to the cochlea are ruled out.

Is there a practical method for shielding? I mean using materials for simple attenuation, and/or altering characteristics of waves (frequency, phase and/or amplitude).
 
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A metal plate provides some shielding. For complete isolation, a closed metal box called a Faraday Cage.. But shielding does not change frequency. Phase is irrelevant.

Note that I did not mention a tin foil hat above. :smile:
 
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