Originally published at: https://boingboing.net/2018/03/19/the-cuban-sonic-weapon-att.html
…
5 Likes
Seems reasonable. Given Canadians were affected too and the Cuban government’s response was “We don’t know what it is either, wanna send in the FBI to check?” rather than “how dare you!”, I immediately thought it probably wasn’t them.
22 Likes
Wireless intermod is a common issue with wireless microphones. We have special rf coordination software that we use to avoid putting transmissions on frequencies affected by rf intermods.
6 Likes
Those frequency response graphs shown in the video look like classic comb filtering from two different frequencies combining. The 7k peak could well have been an artifact of the microphone used to capture the data. I would buy that this is two ultrasonic signals combining to become audible or even more likely ultrasonic signals that cause lower frequency resonances in less than perfect transducers or environments. Heck it could just be cheap fluorescent ballasts.
But ultrasonic jammers, really? I remember he security paranoia over marketers emitting ultrasonic chirps to identify which devices might be near each other and therefore be owned by a unique user. I suppose in the spy vs spy world that might be a way of having a low bandwidth connection to an otherwise secure device.
8 Likes
Never ascribe to malice that which can be more easily explained by incompetence…
13 Likes
I agree that audible signals can easily be produced by the sum and differences of two ultrasonic signals when they mix, I disagree that it only takes place in the microphone. Such mixing will take place anywhere there is a non-linear mixing of those signals–like in the canals in the human ear. Maybe that’s no disagreeing so much as clarifying or extending what you’re saying.
A little background for others: when you take two different frequencys and pass them through a nonlinear thing (in radio we use diodes and other devices, but the human ear is nonlinear as well and would serve the purpse for audio signals) you get sum, difference, multiples, sums of multiples, differences of multiples, etc. The strongest signals are the sum and differences. But, even though they are the strongest, they are a tiny fraction of the power of the original signals.
So, to have enough of the audio range difference signal to cause a human physical damage would require two ultrasonic signals of such intensity that fabric would vibrate and fall apart. Dust would float around in the air and never settle out… It would be like some kind of ghose movie with all the crazy stuff that would be caused. So help you if you had anything with a mechanical resonance near the ultrasonic frequency. It would ring like a bell constantly and probably tear itself apart if it wasn’t metal. If it were metal, it would vibrate with such intensity that touching it would hurt and cause symptoms like burns.
5 Likes
I thought it was established that exposure to ultrasound was known to have psychological or physiological effects? But then, I didn’t know about ultrasound room-occupancy sensors until now either.
2 Likes
Overblown paranoia from the US on a matter relating to Cuba?
Oh, surely not. Next you’ll be saying that this isn’t the first time the Americans have overreacted to an imaginary attack.
5 Likes
But bad engineering just seems much more likely than a sonic weapon.
Well yea, if you’re a Deep State operative who hates freedom!
1 Like
Good post. But the signal doesn’t have to be powerful enough to rip apart an eardrum to cause illness. OSHA standards recognize that sounds can cause health problems at much lower levels.
2 Likes
Hah. Maybe I should offer to work there for outrageous pay. I couldn’t hear anything in that video. My hearing is pretty much nil above 4000 Hz.
1 Like
Okay but this sounds like an audio beat frequency issue, like one transducer operates at 22Khz and the other at 17Khz, resulting in sound at 5Khz.
What are the odds for an US apology to Cuba if this is proven to be the cause?
2 Likes
The sheer power levels required seem like they would imply at least recklessly negligent engineering; though not necessarily an intent to build a weapon. Sound intense enough to be a serious risk to hearing isn’t terribly uncommon either in occupational exposure or even voluntary music listening; but sounds intense enough to cause neurological damage(especially ones that are ultrasonic only; not the ‘is it sound or the atmoshphere beating you up?’ you get near explosives and the like) must be a bit of a special order item; and one where someone should have raised the ‘and you want to put this thing where?’ issue.
1 Like
Or when Clinton bombed Sudan’s largest pharmaceutical factory, or Bush the second invaded Iraq on false pretext or Reagan supplied terrorists in Nicaragua. I know the odds for an apology aren’t good, but they have to be at least somewhat larger than none.
2 Likes
This story has always been fishy, with lots of elements that just don’t add up. Like the attacks taking place in hotels and residences, but not at the embassy, and being precision-targeted to affect certain individuals but not bystanders (of which there would be many in a hotel). AFAIK there have been zero reports of anyone other than mostly US and a few Canadian employees affected.
Jammer-vs-transmitter sounds like a weird explanation, but it isn’t quite as goofy as the Cubans either having, or allowing a third party to use, an ultra-high-tech sonic weapon that can be used stealthily and targeted precisely.
2 Likes
This topic was automatically closed after 5 days. New replies are no longer allowed.
