From Jim Soper:
If you want to know if a voting machine has active WiFi (wireless), you can use a laptop or some handheld devices such as a PDA or Cell Phone.
Better would be to get a directional WiFi locator, because it can tell you not only if WiFi is present, but what direction it’s coming from.
I asked a hardware techie friend of mine, and he suggested buying the following device: Hawking – HWL1 – 802.11b/g WiFi Locator
It’s listed at TigerDirect.com
Neither my friend nor myself has actually used this, but I think I’ll get it or something similar in the next week.