Re: The Cold War spy technology which we all use - Theremin
I read that article with interest.
It worked on about 1GHz and used a cavity resonator with an audio diaphram as one side of the cavity, audio would phase modulate the reflected signal and be demodulated with what was effectively a direct conversion rx.
I experimented with and worked on a very similar system.
These days any high power illumination signal instantly raises attention from counter espionage types - plus you can determine exactly where the illuminating signal is coming from.
Mods - please delete this if not considered appropriate.
__________________
Building and tinkering for over 50 years, from 807's to digital amateur TV.
|