Posted on 03/11/2018 7:31:13 AM PDT by grumpygresh
Do any of you have knowledge or experience with voice jammers (not cell phone jammers which are illegal) to block recording of conversations? What about microphone detectors; do they work? What kind of covert microphones do undercover agents use and where do they wear them?
You need a microphone broom (sweeper).
Shoephones!
But seriously, you could just about hide an inexpensive but good quality wired recording devise anywhere these days, even in a cuff of your coat or in a tie.
Microphone detectors to my knowledge work on RF detection for wireless. I’m not sure what can be done about wired.
Try white a noise generator.
Most phones can record audio. Microphone detectors really detect the rf of a transmitter, not the microphone itself. But these days you would have to detect such a wide frequency range (525 khz to 2.4 Ghz or more) at such a low power that it is an impossible task for an amateur.
Even a pair of bluetooth earbuds can pair with a phone and record audio.
A mic detector but a jammer yes.You can flood the zone with inaudible white noise.
You can flood the zone with inaudible white noise.
It’s a White thing, you wouldn’t understand.
I could tell you that, but then I'd have to kill you.
Regards,
A MEMS microphone is about the size of a grain of rice, so it can be placed virtually anywhere (consider the hearing aids that fit entirely inside the ear). If you are unaware of where a surveillance device may be present, it’s impossible to “block” it from communicating or storing information that it picks up. You can only obscure the information you want to be private by making it difficult to pick up (i.e. by whispering) or by obscuring it in interference such as white noise or other sounds that will appear as loud or louder to the microphone and thus make it more difficult or impossible to understand what is said. Of course the time-honored spy movie notion of turning on a radio or TV is an example of this but modern DSP methods are vastly more effective at separating information from noise than most people would expect (consider the devices that extract vocals from song recordings leaving only the music track for karaoke purposes). There are surveillance methods that detect the vibration of glass windows caused by voices insidea a room, and spread spectrum radio transmitters that are virtually undetectable.
No means of protection is foolproof and 100% effective, you can only do things that make it more difficult for someone to listen in.
Practically speaking, since audio in that range is fairly directional, and you need a lot of power, the utility of such a jammer is questionable. It would of course probably drive away every rodent and dog in the neighborhood.
Some people suspect the sonic injuries that occurred in Cuba to our diplomats resulted from interaction between ultrasonic sources, so I would not encourage anyone to make such a jamming device at home, or expose anyone to such a strong ultrasonic audio field. It could be hazardous, so leave that kind of thing to research labs.
Alexa seems to do whispering just fine.
Just Google pen camera with audio and take your pick.
Remove the magnetron from a microwave oven.... turn it on....
Lots of white noise
Unsheilded ignition type system..
No, even if a microphone had response that extended to that frequncy range (very doubtful in a mic intended for voice surveillance), it will respond to all frequencies and a simple filter would remove your jamming signal leaving the voice intact. But no one interested in surveillance would consider using a mic with response higher than the voice range so it’s a moot point. In any case, it wouldn’t work.
You just use a small RF white noise generator. Mics are passive so pretty much impossible to detect (think phone). In the old days you had to modulate tape to record so you could detect that, not true now. So you have to “wash out” the audible content. Not foolproof because you can extract the content with filtering.
I don’t know about “inaudible” white noise but I have used white noise generators to adjust speakers before... many amplifiers have the function built in so you can use a calibrated mic or spectrum analyzer to adjust for speaker weaknesses or dead spots in your listening room.
If you are truly worried about being recorded simply make sure there are no recording devices allowed where you are meeting... cell phones should be put in a metal box at least xx feet away so BT cannot connect and the phone itself cannot hear... play white noise over the stereo... if there are windows dampen them out with sponge rubber or some other deadening.
I'm thinking "Alice In Chains" or "Nine Inch Nails", played at volume 10.
I saw something about a technology where they use lasers to pick up the vibrations in glass windows to spy from a distance. I didn’t know that they were doing this for a long time.
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