When I was a child I could always hear a high pitched whine from nearby CRTs that adults couldn't. I'd always assumed that to be a mechanical effect due to the varying magnetic fields, but perhaps this was the mechanism?
That sounds more like coil whine, which is “normal” sound (i.e. moving air) from components vibrating rapidly. That’s not what this paper covers (= more like people’s brains “imagining” sound due to RF triggers)
The reason you remember adults not hearing it is because there is a well-documented loss of high-frequency hearing as people age.
(Which has even been “weaponised” before; there were stories some years ago about stores blasting high-frequency noise outside to deter loitering teenagers without affecting desirable adult shoppers)
> Which has even been “weaponised” before; there were stories some years ago about stores blasting high-frequency noise outside to deter loitering teenagers without affecting desirable adult shopper
Yeah, they should only work for teenagers. Except for when you are visually impaired like me. I'm almost 35 now and still hear those high frequency noise. It is extremely annoying and even borderline painful. Last year I even got the cops involved when a parked car in front of my apartment constantly emitted a high frequency noise for deterring stone marten and I didn't know who the car belonged to. It was a pretty funny interaction in the end because none of the parties involved (except for me) could even hear the noise. But the car owner admitted they had such a device installed. Resulting in them just moving their car.
The ability to perceive high frequency sounds decreases statistically with age -- but that certainly doesn't mean that all people lose the ability to hear them when they're older (and it also doesn't mean that all people can hear them when they're younger).
It's a distribution. Probably a normal distribution, but I don't know that for certain.
That's normal. CRTs emit a faint sound at just under 16kHz, which is in hearing range for most children but not most adults as the upper end of this range naturally decreases with age. The article is about radio frequency electromagnetic waves, at much higher frequencies.
It can be a bad flyback transformer some leads loosen and you get a whine. Power is 60Hz in US and Canada but the whine is much higher than 60Hz.
Even a properly working CRT TV had the very high pitch whine. Any kid from the 80s or I guess 90s and back knows of the CRT whine. I recall it so high it's almost like it's in your head as imaginary or you could "taste" it in your 1970s/80s mercury amalgam fillings (maybe that was just me).
You lose that ability of your hearing pretty early in life or early teens (loud music damage?) but it couldn't be more than 20KHz the highest pitch of sounds that humans can hear.
I don't belive I could ever hear CRTs, but I belive I had a similar experience. I once saw a meteor in the night sky of France and also heard the sound it made. I was assured by my father, who knows of such things, that the meteor was way too far away and in too rareified an atmosphere for me to have genuinely heard it's sound. However, I later learned that meteors can emit low and high frequency electro magnetic radiation. Perhaps this was what I heard.
Having repaired a few CRTs, this whine typically only happens on aged parts. My son can hear it, but I cannot. From what I understand, as the coils move from vibration over time, this whine gets worse, calling for realignment.
The odd thing is I don't remember hearing it much as a kid in the 90's, which is why I associate it with the age/condition of the equipment. These days, every CRT I bring home is the bane of my son's existence if he is in the shop with me, but I can't hear a thing (due to the age of my equipment)
I definitely heard it in the 90s, in 1990/1991 my university had a lab full of televideo 910 and 905 terminals that were maybe 5 years old, suffering from massive burn-in and a lot of them whined really bad, giving me a headache if I had to use them (the 905s seemed to be worst at this).
My first job also involved a dec vt240 with the same features - really badly burnt-in display and horrific coil whine that made me go home with a migraine at least twice that I remember.
It makes much more sense when you realise that the 16kHz or so frequency is well out of range for anyone over 40. Many things related to noise make sense once you realise all older people are near deaf, compared to the hearing of a 10 year old.
I'm 33 and I can still hear CRTs. It's definitely a sound and not a radio frequency: if you install a spectrogram app on your phone, you can see it at around 16kHz.
Then I suppose a broadband RF detector can be made by aligning a tube of brine towards a source. Alternatively a 3D microphone array could be employed in an ocean.
External noise floor probably sets the maximum sensitivity, but should be possible to process most external noise out
I've told my kids and some others about my ability to hear certain RF emissions. I know it sounds crazy, but it's true. Thanks for posting this paper! I'm glad somebody did the research to prove I'm not crazy.
I can hear a local FM radio station if the room is quiet but a fan is blowing air. At first I thought it was just one fan that did it, but it seems to be almost any fan.
Most of the time what I can hear is just at the edge of my hearing, but the past few weeks it's been loud enough to occasionally ID songs that are playing (they play 'Paradise City' and 'Living on a prayer' quite often, which are very easily ID'ed because of non-language vocals in them - ie the 'Oooooh' parts).
I figure that the fact that the antenna is about 500m away is probably a good portion of the reason it's audible, but whether it's actually acoustically audible, or just RF that I'm pseudo-hearing, I don't know.
I used to logically assume that when people could 'hear' radio it was only possible with AM because FM modulation shouldn't be demodulated in resonant cavities like AM is, but this station has no AM presence, only FM and DAB.
Not conclusively, I guess, but it's there at any time the conditions are correct (ie, a fan moving air somewhere in the apartment, and otherwise silence).
It, however, sounds nothing like an acoustic leakage sounds, I'd describe it more as envelope-shaped white noise then filtered to a range of 'high' acoustic frequencies (maybe 8-14kHz, but I'm guessing); whereas structural leakage of audio has a different profile more in line with being low pass filtered.
I have heard leakage audio from the only neighbour that it COULD be from, of their TV and Radio audio, and that has the normal low-pass sounding profile as you'd expect.
So while I can't rule out that it could be leaked audio, it 'doesn't sound like it' to me.
I grew up in a house that was next door to a radio rebroadcasting facility, and we could definitely hear the radio station coming from the walls of our house sometimes, e.g. even their station identification so there was no ambiguity. I assumed it was the house wiring (mostly knob and tube) acting as an antenna. I'm reasonably sure that was AM, though.
In a quiet room I can hear some faint 'tick tick' noises if I place the back of a cellphone against my ear. I live near cell edge so my devices broadcast at max power. These sounds do not happen when wifi is turned on (lower power level) and are not the old GSM signal that gets picked up by analog circuits.
If it's not RF, it's likely some other component inside the phone resonating when it transmits. There's sometimes some higher frequency tones mixed in but in general this doesn't sound high pitched. I remember reading something about soviet experiments with humans exposed to strong microwave radiation and hearing it as 'clicks' in their head.... so maybe?
I have actually heard a similar thing when having my head on my pillow with my phone on my mattress. Is yours a spring mattress? Im curious if that could contribute
No, my mattress is foam. My guess for you is the pillow isolates noise around the phone so it's easier to hear and the added RF attenuation by bed/mattress material makes it send at higher txpower.
There is very low-freq hum in cities (because of cars wheels, airconds, all those rotating+vibrating things), which can be (un)heard if one goes above and then beyond/down edge of some hill at end-of-city - and will stop hearing it (absorbed by earth mass). But it is difficult to "hear" inside the city as your body also vibrates with it..
Possibly? In this paper they say the frequency needs to be between 2.4-10,000 Mhz and to be over a certain power threshold. Also the individual needs to be within a certain distance and have sensitive enough hearing (over 5000 hz).
Your only other post seems to be entirely unrelated? It talks about silicon CPU trojans and remote computer interference, which is unrelated to radio signaling biological matter, much less neural interaction. And I hate to scare you more but it doesn't even take into account that Ethernet over powerline is a thing and bad actors are just as likely to use PSU trojans to send commands to individual or multiple computers over the power grid if they're doing the same with radio waves
https://news.ycombinator.com/context?id=36547321
being harassed by governmental or other terrorists with access to advanced rf weaponry has been a common delusion in schizophrenia for decades, to the point that aluminum-foil hats are a cliché in popular culture
