Hacker News new | ask | show | jobs
by yohui 3217 days ago
I don't think generic hate would help you get ahold of sonic equipment. A plausible sounding theory I've heard (and I stress that it's total speculation) is that someone was trying to spy on the diplomats but miscalibrated their ultrasonic eavesdropping device, turning the effects harmful.
1 comments

I've heard that theory a number of times. I'm no expert in acoustics or eavesdropping, but I would assume that ultrasonic eavesdropping equipment would involve highly sensitive microphones, not powerful speakers.

Is there some sort of ultrasonic-carrier-signal microphone out there, akin to laser mics?

Think of a bat. It clicks and the reverb is what its ears interpret to understand surroundings. Output can be used to trigger/power passive listening devices. I always think of the Russian gift to the US embassy that was a wooden seal with a passive bug in it. Scans didn't catch it for years.
That was activated by and transmitted radiowaves though.
Hmm... A speaker is a microphone. I am not sure if that is salient, but it seems worth noting.