See also: https://en.wikipedia.org/wiki/Cryptonomicon

...and the entertaining tangent story involving Van Eck Phreaking and vintage furniture.

Markus Kuhn’s work on “optical eavesdropping” — reconstructing a CRT image from reflected visible light — is really interesting: https://www.cl.cam.ac.uk/~mgk25/ieee02-optical.pdf

This SDR implementation looked really interesting for sniffing monitor output - https://github.com/martinmarinov/TempestSDR

Alas I don't have a suitable SDR to try it with.

If you want to play around with Van Eck Phreaking, try https://packages.debian.org/sid/tempest-for-eliza , which lets you listen to MIDI-like music via AM radio from your computer monitor.

Unrelated, but at the bottom of http://celeriac.net/sx/public/ is a sonification of Van Eck's sequence