How To Build A Tin Can Waveguide WiFi Antenna
 

Got no dough for a commercial WiFi antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantenna, may be just the ticket. This design can be build for under $5 U.S. and reuses a food, juice, or other tin can.
I am not an electrical engineer, nor do I have access to any fancy test equipment. I've built some antennas that worked for me and thought I would share what I learned. I have no idea if this is safe for your radio or wireless network equipment. The risk to you and your equipment is yours.

Building your Cantenna is easy, just follow these steps.

1) Collect the parts
2) Drill or punch holes in your can to mount the probe
3) Assemble the probe and mount in can

http://www.turnpoint.net/wireless/cantennahowto.html