On Mon, 20 Aug 2001, Faustine wrote:

emissions are simple to decode. Though in theory LCD screens emit less than a VDU, recent EMC controls have greatly reduced emanations from VDUs--with the result that the graphics card will often be the greatest source of compromise.

I'm not an expert. However, you can make extremely silent devices. It's not rocket science, and one of the major points towards wearables. A LART board burns about 1 W, and a hud type of display is low power. With less than braindead engineering this is trivial to shield. A hud which contains a built-in framebuffer will be essentially impossible to detect. If you want to grow fancy, you can even encode the serial links sending commands to it. Can anyone give me real world data on HF signature of a Twiddler2?