http://www.reddit.com/r/RTLSDR/comments/1le3if/so_i_discovered_that_my_hp_la... So I discovered that my HP laptop leaks/transmits its built-in mic audio somewhere around 24Mhz (self.RTLSDR) submitted 23 hours ago by cronek I accidentally stumbled upon a signal in the 24MHz range, appearing to be 4 carriers. I tuned to it and heard silence, then someone came into my office and started talking and I could hear them speak. The signal appeared to be coming from my other laptop (not the one running the SDR) and was pretty weak (my antenna, the crappy one that comes with the dongle, stuck to a metal stapler was right next to the HP laptop). Here's a picture Both mics transmit independently, in the picture I rubbed one mic. The signal appears to be mirrored. When I tap the microphone, or make a loud noise that would clip the preamp, the signal drifts off and then slowly comes back to its original frequency, as illustrated here (only one of the two mics drifted, if I hit it harder or clip both mics, both will drift). I'm pretty sure that if I build a nice high-gain antenna optimized for 24Mhz I would be able to pick up the sound from some distance away. The laptop is an EliteBook 8460p. I have checked identical laptops and they do not transmit at this frequency. I didn't have the time to scan the full spectrum though. I'm guessing the preamp is really crappy and somehow ends up transmitting FM at HF freqs. Anyone has any ideas about this? I work in a high security setting and having laptops transmitting audio from everyone's office/meeting room etc is a really big deal. I somewhat doubt it to be an intentional listening device due to the weird frequency drifting. For now I guess I'll just disconnect the mic preamp pcb.