Answer: You’ve probably heard of the WiFi antennas made from old Pringles cans, but those are tricky to build and often require special connectors and soldering. A much easier option is a parabolic reflector antenna. You can whip one together using an old shoe box, tape, and some aluminum foil in about 30 minutes, and it will double or triple the range (in a single direction) of just about any wireless access point with an external stick antenna. It works by simply creating a large surface area that the antenna uses to receive and transmit signals.

First, cut two parabolic curves from cardboard, and cut a hole at the focal point of each just big enough to fit over your access point’s antenna. These curves keep the reflector in its proper shape. Next, cut a piece of cardboard roughly 9 inches square, and cover one side with aluminum foil. Shape the square sheet over the two curved pieces, foil facing in, and tape everything together. Try to get the reflector to fit to the parabolic curve closely, as deviations of even a quarter of an inch can reduce its effectiveness. Finally, slide the completed apparatus over your access point’s stick antenna.

This story has been updated. It was originally featured in the June 2005 issue of Popular Science magazine.