From Bruce Schneier’s “Crypto-Gram” (15 August 2005):
At DefCon earlier this month, a group was able to set up an unamplified 802.11 network at a distance of 124.9 miles.
Even more important, the world record for communicating with a passive RFID device was set at 69 feet. Remember that the next time someone tells you that it’s impossible to read RFID identity cards at a distance.
Whenever you hear a manufacturer talk about a distance limitation for any wireless technology — wireless LANs, RFID, Bluetooth, anything — assume he’s wrong. If he’s not wrong today, he will be in a couple of years. Assume that someone who spends some money and effort building more sensitive technology can do much better, and that it will take less money and effort over the years. Technology always gets better; it never gets worse. If something is difficult and expensive now, it will get easier and cheaper in the future.