As an electrical engineer (but a new one, so take this with a grain of salt) it really is kind of staggering. This probably could only have worked with the sel

As an electrical engineer (but a new one, so take this with a grain of salt) it really is kind of staggering. This probably could only have worked with the selectric- they're quite special and if you haven't seen one in slow motion it's a thing of beauty[1]. The bug only had to measure magnetic disturbances in a few dimensions to recover text, and because it can measure the amount of time it takes to locate a new letter the field measuring error is much more acceptable. You wouldn't be able to do that with a more classic typewriter. The level of sophistication here reminds me of current research[2] using software-defined radios. I'd LOVE to see a diagram of this thing. Old circuits were elegant by necessity, and something this sophisticated has to be a work of art. > It contains special components to hide its presence even from non-linear junction detectors (NLJD) That's really amazing. NLJDs work by blasting broadband noise at a circuit- any internal wire trace gets turned into an antenna, and if it's attached to a transistor or diode it'll re-radiate at multiples of the frequency. Typically you can even find just chunks of metal touching a semiconductor with those... the fact that they evaded detection is very impressive. [1]: https://www.youtube.com/watch?v=izZ02t2UEGc https://www.youtube.com/watch?v=izZ02t2UEGc [2]: https://www.youtube.com/watch?v=VZ7Nz942yAY https://www.youtube.com/watch?v=VZ7Nz942yAY