I was playing around with a usb audio dongle, and I noticed there's this very regular weak audio signal emanating from somewhere.
My first thought was a mechanical harmonic from a switchmode recharger... however it's pure sine wave signal at 1040 Hertz, with no harmonics like pulse waveforms would have, it occurs regularly every 40 minutes, and the tone is keyed at a precisely 2 Hz rate. And as you can see there's a binary value in there (or "MR" in morse code?)
Anyone heard of 1040 Hz being special? Is someone's smartphone doing that illegal advertiser subaudio surveillance shit?
Are there any devices you could use to find where it's at? like a device that measures the strength of the signal and tells you if your getting closer or farther? How did you make this discovery?
Sure, an oscilloscope program that does an audio spectrum running on a tablet that I can point about... but it'll be like a 40 minute wait, and the housemate's bedroom is off-limits.. (the one with the iphone--and I'm not about to go up to them wearing a TINFOIL HAT).
microphone -> 40dB class A mic amplifier -> usb dongle -> computer -> audacity
legacy radio broadcast for calibrating analogue equipment?
Gavin Kelly
It may just be some kind of electronic static. I had an alarm clock radio with random buzzing coming from the speakers even when the volume was on low. Unplug and power off all of your electronics and then try it again, it may just simply be elecronic noise.
Lucas Walker
electronic 'static' doesn't behave that regularly. It's every 40 minutes to within 1/100s. the keying of the tone 'data' is also just as precise.
Levi Wood
1040 Hertz is also not a harmonic of anything clock-like, and there's no other signals except at that frequency (nothing that 520 or 2080 Hz)
Michael Price
Time to triangulate and find the source. After that you can make suppositions.
Bentley Cruz
Good point, perhaps it's some kind of battery powered remote spycam or something of the like that's scheduled to exfil data at certain times. good luck user, post results once youve found it.
Xavier Diaz
ITT: schizoposters Guaranteed OP will shamefully abandon the thread once he finds out it was just coil whine or some other bullshit (or he goes off to chase his next conspiracy theory)
Ayden Hall
Do a binary search: turn off half of all potential sources (consider your housemate's bedroom a source that you don't turn off) and see if the signal reoccurs within the next 40 minutes. If it doesn't, that means the source is among the turned off potential sources, or vice versa. Repeat until only one is left. Results guaranteed in O(log n) if you haven't omitted a potential source.
Robert Stewart
You think that might come from the dongle? Chinks sometimes bug random shit. Turn the amplification on the microphone all the way down and see if you still pick up anything.
Jaxon Hughes
You can do it faster by starting with triangulation to get an approximate location. The precision of triangulation depends on how consistent the signal's strength is and how precise your measurements are.
Jonathan Ramirez
Well the sound IS probably coil whine. It however indicates that something is operating at regular intervals like that. For what you know the coil COULD actually be powering a transmitter.
Thomas Martinez
Going to try different USB dongles today. fwiw, the above was recorded with a Sound Blaster Play! 3
Leo Richardson
Same signal, different dongle. (And that's probably a Morse 'L')
You can communicate over audio if both devices have mics and speakers. It's a way to avoid detection. Someone had mentioned data transmission underwater through sound. Sound and recieve data with audio pretty well. And you can pretty much translate the way computer talked over telephone with tones. I think you can get up to 4Mbps over with audio. That's enough to exfiltrate data at slow trickle and run without any need for networking and can't be detected with networking packet collection. My thoughts were that this kind of stuff was done in the ultrasound frequencies so it could not be heard.
There were experiments with something similar but using screen flickers and webcams. But the rate of transmission is lower than whatever the refresh rate on a given monitor so it's really slow.
But as mentioned, it's probably some kind of static.
Here's some autistic trivia for you. You know sometimes your computers speakers will make a noise right just before your cell phone rings? You can hear WPS requests on the cell phone. I was doing a WPS PIN search on my home router with reavers and I was talking on the phone. I could hear the requests. You can probably hear authentications and things like that as well.
Question can you hear any of this over your cell phone when it's going on?
Owen Taylor
I have a Ham Radio licence (equivalent to the 'Extra' in the USA), so I don't need the technology for babbys drill. (fwiw, I first noticed the signal when running WSJT-X between two laptops without radios, and seeing how far and how attenuated I could go..)
Definitely looking like it's the housemate's iphone now, as I left the recorder running during the weekday when we were both at work, and the mysterious tone only appeared when they were around.
Daniel Moore
He probably installed some rouge data gathering app while browsing porn
Christian Smith
Interesting.
Without getting carried away with the tinfoil, it's possible the roommate has installed some app that's emitting ultrasounds that are allowing him to be tracked. Theoretically, you could set up 'beacons' all around town to listen for these uniquely identifiable yet inaudible signals, and get an approximation of his location every time it was emitted. Current day Bluetooth and WiFi trackers work on this principle.
Xavier Gutierrez
Was going to say that it was probably an old longwave beacon that hasn't been decommissioned yet, but now it doesn't sound like it. You can pick up longwave beacons by just sticking the end of a large spool of wire into your mic jack. Boom, longwave radio with bigass antenna.
Elijah Green
'uXDT tracking' is this
Ryan Brown
There's a few orders of magnitude difference between 1040 Hz and 1.040 MHz..
Run airodump-ng and read run a script to read through the CSV once every so often and RE for whatever MAC address you are tracking. That's funny I just though of something. If you are running your you wireless card in monitor mode you can still communicate via audio while your NetworkManager is stopped.
Honestly I like the idea of this technology. Send data over sound and communicate over sound. It's a low bandwidth low range convert communications channel.
You could send data through aluminum for probably greater distances or if there's is some part of the building's structure like plumbing pipes or framing. But probably they have something.
Here's a theory anons. If you have a sound device that can exfiltrate data but at limited range you can use sound to vibrate something like a window in the room you can use that vibration. You can use the object to modulate light reflected from it. Something like a lazer listening device. youtube.com/watch?v=Ylo72DyapVY
