The typical defense is a 'Faraday cage', a conductor surrounding whatever emissions you want to stop. If the cage is made of mesh, then frequencies with wavelengths less than a quarter of the mesh opening will leak out, so if you’re not certain of wavelengths involved, you’d need a solid conductor.

The original van Eck / Tempest had to do with CRT radiation. Now it’s flat panel, but with similar analog signals (but much lower voltage) in RGB, and digital ones in HDMI/DVI and DisplayPort. Given the lower voltages (the voltage in the flyback transformer in a CRT was potentially fatal), the distance any signal might leak had ought to be proportionally reduced

BTW/FWIW, Michael Faraday is one of my heroes. Son of a blacksmith and a servant, he went from a bookbinder who’d left school at age 13 to a member of The Royal Society of London for Improving Natural Knowledge — by reading the books he was binding.