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Microwave Auditory Effect


Enthalpy
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Hello fellow scientists!

The Microwave Auditory Effect, or Frey effect (1962), was observed during the second world war
http://en.wikipedia.org/wiki/Microwave_auditory_effect(prefer Spanish or German)
by people working on radars, who noticed that the microwave pulses created in their head the perception of clics.

It has been nicely explained by the sudden thermal expansion of the tissues heated by the microwave pulse, with the resulting faint pressure wave being felt by the ultra-sensitive cochlea. Not only are figures said to match, subjects could also "hear" through their cochlea the expansion of tissues not pertaining to them, and subjects with disabled cochleas don't perceive the microwave clicks.

As you guessed, organizations wanted to make weapons of it. Thanks to the Freedom of Information Act, the US Army Intelligence and Security Command (USAINSCOM) disclosed a report titled "Bioeffects of Selected Nonlethal Weapons", meanwhile available there (4MB)
http://www.slavery.org.uk/Bioeffects_of_Selected_Non-Lethal_Weapons.pdf
The section "Incapacitating effect: Microwave Hearing" spans from page marks 6 to 8 (where the "Incapacitating effect: Disruption of Neural Control" begins); the Pdf counts them 8 to 10. The main effect as a weapon would be psychlogical, against a target person unaware of the technology.

Frequencies range from <<200MHz to >10GHz, as expected from a thermal effect; 40GHz would only deposit the heat shallower. The perceivable power density is 800W/m2 and the energy 8mJ/m2 over 10µs (40J/cm2 is inconsistent, µJ better credible). Reported ranges exceed 100m. In 1973, Sharp and Groove transmitted not just clicks, but figures.

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I believe to have experienced such a weapon in March 2012 when I fled France as the decades-long conflict with the secret services sharpened - hence I have no doubt about the weapon's users.

At the end of the afternoon, walking on a path after leaving a road, I heard the noise of rain falling on dry dead leafs covering the ground. But it wasn't raining, the sky was absolutely clear. No wind neither. Dead leafs were present. I perceived the noise originating only within 2m radius around me, no farther, as I moved 100m or more. The noise was as frequent and irregular as rain uses to be. I first thought the dead leaves would emit a pop as fresher air lets them deform, but this does not explain why I heard no noise produced farther away as rain or bugs use to do.

I here quite well (musician), had never experienced auditive hallucinations before (but one single similar experience after, less convincing), was calm once I had decided what to do and how, and still not tired.

The next visible human presence was an empty unusual car with tall windows, over 200m away, which would have seen the path at grazing incidence. I didn't notice any object flying above me, but hadn't checked neither. The spooks knew my position: I had just crossed a bridge where an other empty car awaited me. I knew this exact car for years as it awaited me empty at varied locations and supposedly carries a camera; I had already met it when crossing the bridge at the previous valley - so I decided to stay on the hilltops henceforth.

----------

I'm glad to have read about the Frey effect now, as it's the very best available explanation to this rain "noise".

  • Laser shots can produce similar sounds, but impacting everywhere around me, they'd probably have hit me as well, which I'd have noticed.
  • The best location to target 2m around me would have been atop, where I didn't notice anything. The car with tall windows saw the ground around me at grazing incidence.
  • I had thought at a microwave weapon, since the car's tall windows permit a big antenna. But conversion to noise would have needed a huge energy, probably perceived through other, more direct effects. The grazing incidence also spoke against the round 2m disk.
  • I didn't favour then EM waves acting on the brain, as the effect was only audible.

The Frey effect in contrast fits very well:

  • 2m around me because no real sound followed multiple paths that reveal its distance.
  • Only audible effects as is already known, resulting from the heat and pressure waves.
  • The car only needed to target my head, not the flat 2m disk, and its position was adequate for this.
  • But I heard the noise around me, not behind. Sources for the Frey effect tell "generally" behind.

Figures on the transmitter make also sense. Take 10GHz or 30mm wavelength. A transmitting antenna, for instance printed on the car's unusually tall windows, can be almost 1m*1m, hence concentrates the power in 50mrd*50mrd. At 200m range, that's 10m*10m, so 1000W/m2 need only 100kW peak transmitted power - nothing special at radars. If the antenna consists of 66*66 active patches, each one has a 23W amplifier: transistors do 10 times more. Three 50V 3.3µF capacitors at each patch would provide 50W*100µs, a usual pulse duration.

---------

Some lessons I draw or re-draw...

  • Effects observed 7 decades ago can still be puzzling.
  • Spooks make weapons of anything, even if difficult, expensive and little useful.
  • Tinnitus should not be a psychiatric symptom, since weapons can produce it.
  • One good reason more to keep your tin foil hat at hand.
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Hello fellow scientists!

...

  • One good reason more to keep your tin foil hat at hand.
I did read that report when you posted it in Frank's thread. So wouldn't you need your entire head screened? Even then, might the signal get in through your neck? Perhaps a tin foil/screen suit. For sure, just because you are paranoid does not mean someone is not out to get you. :ph34r:
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There were rumors that the 1960s era MiG-25 Foxbat radar, could kill or incapacitate small animals in front of its dish antenna, if activated on the ground.

I have 'heard' this numerous times on military aircraft forums, but have never investigated it further.

 

So why were the 'spooks' after you ? Or would you have to kill us after you told us ?

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[...] wouldn't you need your entire head screened? Even then, might the signal get in through your neck? [...]

 

I've observed it only once, maybe twice but that was much more doubtful, so the rest would be supputation only. Range needs to concentrate the power, and the corresponding short wavelength won't circumvent an shield much, so the shield should cover parts from where the cochlea can pick pressure waves - rather wide. As opposed, the cochlea picks sounds at radio intensity well below nerves get excited, so the spine wouldn't need an extra protection.

 

The other solution is just to be aware of the gadget. Clicks or sounds are disturbing if you imagine that they're real or that you mishear them. If you know the weapon, who cares a few additional sounds known to be artificial?

[...] For sure, just because you are paranoid does not mean someone is not out to get you. :ph34r:

 

Variant: there certainly are some snakes around here, but you don't need to worry, as one doesn't even see them.

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I've observed it only once, maybe twice but that was much more doubtful, so the rest would be supputation only. Range needs to concentrate the power, and the corresponding short wavelength won't circumvent an shield much, so the shield should cover parts from where the cochlea can pick pressure waves - rather wide. As opposed, the cochlea picks sounds at radio intensity well below nerves get excited, so the spine wouldn't need an extra protection.

 

The other solution is just to be aware of the gadget. Clicks or sounds are disturbing if you imagine that they're real or that you mishear them. If you know the weapon, who cares a few additional sounds known to be artificial?

Good luck then with your hat. One other note is that to concentrate/focus a microwave emission, one would want to use a horn and not a dish. Such a wave guide need not be large as you imply in your opening post.
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There were rumors that the 1960s era MiG-25 Foxbat radar, could kill or incapacitate small animals in front of its dish antenna, if activated on the ground. [...]

 

I have no opinion about that. Power microwaves do have some exotic effects. I just doubt that only small animals would be affected. Humans may grasp what "in front of" means and flee on time?

[...] So why were the 'spooks' after you ? Or would you have to kill us after you told us ?

 

I have to kill nobody and would have no difficulty speaking about it. It would just be off-topic in this thread and off-forum in the Classical physics.

[...] to concentrate/focus a microwave emission, one would want to use a horn and not a dish. Such a wave guide need not be large as you imply in your opening post.

 

Every book states that at identical directivity, a horn has the same size as a dish and as a synthetic antenna, and this is my understanding as well. Except for a small edge that the dish uses less efficiently.

 

Presently and without exotic requirements, every designer would jump to synthetic aperture

http://en.wikipedia.org/wiki/Beamforming

Not necessarily with an area fully crowded with dipoles or patches, since just a wide ring of elementary sources is about as good. Synthetic aperture is more flexible and agile, easier to integrate and disguise, better suited to semiconductors.

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By-the-by; have you checked out LRADs? (Long Range Acoustic Device) While a tin foil hat probably won't defend against them, ear muffs might. Can you hear me now? :o

LRAD @ Wiki

The Long Range Acoustic Device (LRAD), also known as a sound cannon, is an acoustic hailing device and sonic weapon developed by LRAD Corporation to send messages, warnings, and harmful, pain-inducing tones over longer distances than normal loudspeakers. LRAD systems have been used to counter piracy, as non-lethal crowd control weapons, and as communication devices. ...


LRAD Homepage: >> LRAD Corp.


PS If it was me on that path and the van unoccupied, I would break into it and see what's what. Little counter measure never hurt. But that's just me. >:D


...I believe to have experienced such a weapon in March 2012 when I fled France as the decades-long conflict with the secret services sharpened - hence I have no doubt about the weapon's users.

At the end of the afternoon, walking on a path after leaving a road, I heard the noise of rain falling on dry dead leafs covering the ground. But it wasn't raining, the sky was absolutely clear. No wind neither. Dead leafs were present. I perceived the noise originating only within 2m radius around me, no farther, as I moved 100m or more. The noise was as frequent and irregular as rain uses to be. I first thought the dead leaves would emit a pop as fresher air lets them deform, but this does not explain why I heard no noise produced farther away as rain or bugs use to do.
...

A less sinister explanation would be that your passage was disturbing wildlife beneath the leaf cover. Shrews, mice, snakes, beetles, worms, etcetera.
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Break into the van: yes, but (1) only if I had understood it on time and with good certainty (2) approaching it would have been dangerous if it was efficient at 200m (3) I was fleeing the country (4) In case of error, it means damaging someone's property.

 

You know, I was certain that the noise was abnormal, but didn't imagine it originated at the cochlea, so 2m radius around me suggested a source atop, and the van was a remote possibility. I read about Microwave Auditory Effect three years later, and the van must have moved meanwhile.

 

To minor variants, it's the eternal advantage of the attacker over the defender.

 

A loud acoustic transmitter isn't exactly what a secret service wants usually. But unexplained sounds at one or few target persons fit better.

 

Wildlife: I thought at it, and as well at dry leaves cooling down in the evening, but neither explains why the "noise" seemed to originate only from 2m radius including before and after me - something I'm positive about. When rain falls on dry leaves (the imitated sound), you hear it at varied distances, so it's not a matter of near-field or anything.

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Break into the van: yes, but (1) only if I had understood it on time and with good certainty (2) approaching it would have been dangerous if it was efficient at 200m (3) I was fleeing the country (4) In case of error, it means damaging someone's property.

I would be breaking in because -of course- I thought I heard someone calling for help from inside. If called to account, hero not villain. :)

 

You know, I was certain that the noise was abnormal, but didn't imagine it originated at the cochlea, so 2m radius around me suggested a source atop, and the van was a remote possibility. I read about Microwave Auditory Effect three years later, and the van must have moved meanwhile.

Confirmation bias.

 

To minor variants, it's the eternal advantage of the attacker over the defender.

Security against defeat implies defensive tactics; ability to defeat the enemy means taking the offensive. ~Sun Tzu

 

 

 

A loud acoustic transmitter isn't exactly what a secret service wants usually. But unexplained sounds at one or few target persons fit better.

Such judgments are by necessity, secret. ;)

 

Wildlife: I thought at it, and as well at dry leaves cooling down in the evening, but neither explains why the "noise" seemed to originate only from 2m radius including before and after me - something I'm positive about. When rain falls on dry leaves (the imitated sound), you hear it at varied distances, so it's not a matter of near-field or anything.

The sound would be nearby simply because the critters are only disturbed to activity when you are nearby. When you aren't nearby, they are quiescent.
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The sound would be nearby simply because the critters are only disturbed to activity when you are nearby. When you aren't nearby, they are quiescent.

 

Also 2m at right and left, and 2m in front, and stopping 2m behind? Critters would have been disturbed just in front of me, not in advance nor at the sides. And I didn't see any neither, despite hearing thousands of rain impact sounds.

 

Also, it wasn't by far the first time I walked on dry dead leaves on a clear evening in North-Eastern France.

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I trust audio patterns even less than visual ones. Especially when it comes to vague sounds like rain on falling leaves.

 

I was firmly convinced one night that a woman was walking up and down the sidewalk beneath my bedroom in high-heeled shoes, because that's exactly what it sounded like. And every time I went to the curtains to see her, it stopped.

 

It turned out to be the plastic piece on the end of the curtain pull. The evening breeze made the curtains stir, and that set the cord in motion, making it tick against the wall. It stopped when I looked because I was moving the curtain and the pull cord. At the time though, I was absolutely sure of what I was hearing.

 

Water sounds are tricky. I've heard what I thought was heavy wind in the tall pines, only to find out twenty minutes later that river rapids were up ahead, making that constant roar that sounded more like wind at a distance.

 

I'm just very skeptical. We're so good at filling in the blanks in patterns we see and hear.

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The microwave auditory effect is a good candidate to explain an other observation - provided that it wasn't natural.

That other case if far less certain. It was one day later, during a night with moonshine, and I was tired from having walked 30h nonstop through mountain forest.

I had just been located, once again. I believe my enemies tried but failed to locate me when crossing a road; then I had to take a bridge and walk past a house to cross a stream, and there the strong outside lights went on automatically, the dogs barked.

Some 10min after the house, I heard a bird or squirrel hopping on the dead leaves, 20m behind me, on my right just outside the path. I couldn't have seen it in the night, but it sounded very artificial:

  • It lasted for almost 100m: never observed that from a wild animal.
  • The rhythm was perfectly regular, the sound and its intensity too.
  • The felt distance kept constant over the whole sequence.

That time too, I supposed on the spot it was some technological trick. I wasn't convinced by some hopping man-made item because of the regular rhythm on the uneven ground. But the Frey effect now explains it properly:

  • Behind me, as is known from the Frey effect. On my right, because the transmitter was there that time, not in my back as it was for the rain noise, so the pressure waves reached my right cochlea.
  • Regular rhythm and intensity because the machine was programmed that way.
  • Constant felt distance since it wasn't a true sound.
  • A short sound (hop) to limit the energy drawn by the transmitter for each sound.

In case someone doubts: I never have tinnitus nor hallucinations. I was tired, but noticed nothing similar when I wasn't located even after 10h walk more.


[...] I'm just very skeptical. We're so good at filling in the blanks in patterns we see and hear.

 

That's your good right. I too searched more mundane explanations first. Just keep in mind that:

- I was on a path, already far from other sound noises;

- What hits a leaf can't be distinguished, but the sound of a leaf is rather typical;

- It did feel like sound originating only around me.

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About 50m before the hopping sound or pseudo-sound, I may have seen light on the ground - but so faint that it was barely more than the rather clear night, and I was tired, so I'm not sure at all. I noticed it on the path only, not on the darker low plants on the sides; it was some 20m long (or it didn't radiate horizontally), and I don't know if it moved. After thinking at it, I went out of the path and stopped; when I went back on the path I couldn't notice it any more.

I didn't see any light source but had not searched one neither, as I first supposed it was phosphorescence on the path. Though, if it really disappeared, phosphorescence wouldn't explain it.

If this needs a man-made source, it could be a UV light, and what I saw was fluorescence. A source either on the ground (some hills were in direct sight, no visible light there) or in the air, for use in the visible spectrum (but the fluorescence added little to the ambient light) or directly by a UV camera. A quadrocopter drone (I didn't hear any, hence far enough from me) with UV light and a camera would explain it, be cheaper than other gadgets that the spooks use for sure, and as I was awaited in the area and freshly located, an already present drone could have joined my position to confirm I was it.

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First question I would ask myself is: Am I of any possible interest to security sevices? The way you are writing is how an amphetamine addict thinks, when they've done too much; paranoia. Your mind is perfectly capable making things seem real when they are not.

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That wasn't very kind of you. Anyway, no amphetamines (not even Ritaline), no paranoia. No illicit drugs, but some legal drugs against hay fever, and one finger of wine once a month. Few people use less drugs than I do. Why do you imagine such unsubstantiated hypotheses? "Paranoia" being the standard counter to everyone telling about spies, you give a bad impression.

 

And "Am I of any possible interest to security sevices?" is a truly bizarre question - even more so in 2015. It is known universally that secret services spy each and everyone. Or does anyone sensible still imagine that spies are after terrorists and foreign spies?

 

Up to now I haven't told why the French secret services are after me, but I can, and as it seems I should.

 

In this subforum for classical physics, I had expected arguments about power densities, energy storage, that kind of things. I have provided my figures, some references, and I believe they fit. If you have worked on radars and radiocomms as I did, or have knowledge for electromagnetics, just provide your arguments and figures.

 

----------

 

About the possible drone:

 

The French police is known to have some since 2008 "for observation purposes". Needless to say that if the spooks didn't have their owns, they would just borrow them from the police. The only uncertainty is what wavelength they use at night, and if I observed properly and the light did come from a drone, this one would have used UV as I didn't notice the source.

Edited by Enthalpy
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About the faint light on the ground: I had first imagined that the soil was phosphorescent due to some mildew, and that pebbles above it would absorb this light at grazing angle, so I would observe it only at a limited radius around me. That - and the very small intensity too - let me react late and go outside the path.

 

Though, I couldn't see the light any more two minutes later when back on the path. Natural phosphorescence wouldn't disappear within minutes after having holf for hours after sunset. So if my observation was correct - I'm not certain as I am for both "noises" - an external illumination is a better explanation.

 

Meanwhile I've tried the "UV" Led lamps (at 405nm hence visible), and their natural divergence can't illuminate D=10m at a reasonable distance.

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  • 1 month later...

My flashlight has five 405nm cheap Led and, at "night" in a urban area, achieves at 30m a spot of the same diameter I saw and clearly visible. How to compare with fluorescence induced by a more distant source?

  • Efficient fluorescence of paper and some clothes is much brighter than the light that excites it, because our eyes are little sensitive at 405nm. Less efficient fluorescence by mildew or moss is still brighter than the exciting light.
  • Light from a bigger distance stays equally bright if it illuminates the same area, which was the case.
  • The light was but visible then, under much darker conditions than now in a town's garden, so the illumination was much fainter.

Led can be better than on a 5 bucks flashlight. At invisible 385nm they achieve 30% power efficiency, some emit 5W each, the chip's optical power density is 2W/mm2.

  • 100mW UV need a d=0.16mm emitting area.
  • A lens at 10mm from the Led spreads the light on D=5m at 300m distance due to the emitting area.
  • If the beam is 10mm wide at the lens, diffraction adds D=0.03m to the spot at 300m distance, and an imperfect lens is allowed to add more.

Some extreme cameras film under the light of stars but don't fit under a drone. At the other end, a commercial camera takes pictures under the full Moon's light. In between, proper design permits a lightweight camera to make clear images in a less clear night, and fluorescence lets many clothes shine over the background, while the UV source stays unnoticed.

 

One Led, one lens, one camera, all under a drone, far enough to be silent - that's easy technology, and a possible explanation to what I saw.

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  • 2 weeks later...

Because these thread and subforum deal about physics and hard science, but I want to address some other legitimate queries by forum members, I put there

http://www.scienceforums.net/topic/90014-why-do-i-say-the-french-spooks/

a first set of reasons to be surrounded by the French secret services.

 

----------

 

Fun: since I described the suppsoed UV camera here, a blossom of questions appeared elsewhere on the Web about how to make a fluorescent dye with UV absorption as narrow as possible. Under varied usernames, with indirect questions. I can't exclude that other groups want such cameras.

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  • 6 months later...
  • 2 weeks later...

In message #13 of the present thread, I mentioned a spot of very faint light I believe to have seen on the ground

http://www.scienceforums.net/topic/88729-microwave-auditory-effect/#entry866124

 

I had proposed a quadcopter as the light source, but a satellite is a good explanation too.

  • From 30° and 1500km distance and at 405nm wavelength, a lens of D=150mm suffices to achieve the D=20m spot.
  • The electric supply power drops to 10-1W then, and very few people can notice the narrow light beam.
  • Consistent with the silence. I didn't hear any quadcopter in the quiet ambient.
  • Fits my other observation: the satellite getting brighter. I couldn't tell the colour of a faint point in the sky.
  • Laser diodes at 405nm exist for as long as DVD while market-ripe true UV are recent in 2016. 405nm would have been a natural choice on a satellite a few years ago and still now.
  • I had searched for light sources on the hills, not in the sky, so on that occasion I wouldn't have noticed a satellite getting brighter.
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