An anonymous reader writes to mention an Engadget post on an incredibly powerful wifi scanner
. The 'Janus Project', as it is called, can sniff 300 networks simultaneously. It stores and encrypts the data as it receives it, for later use. From the article: "In addition, the Janus Project has an instant off switch, which requires a USB key that has a 2000-bit passkey and a separate password to regain access. What's under the hood? Williams packed an Ubuntu Linux machine running on a 1.5GHz VIA C7 processor with an Acer 17-inch screen into that snazzy little rugged yellow box. Oh, and the closed case is waterproof too, in case you need to transport Janus Project on a whitewater raft to your next hacking hotspot. We don't doubt someone will."
The post leads to a tgdaily article, which offers more details