Here is a classic project used to increase wireless signal strength. Cantennas focus using a waveguide very much like a magnifying glass focuses light. [Robert] made a Natural Light beer cantenna, pictured in the upper left. His approach used three beer cans, a paper towel holder, and a shower curtain rod. On the tipline, he noted a signal boost from 11Mbps to 54Mbps. This is certainly something we can hack together if our room lacks adequate signal. Read about parabolic and seeking versions after the break.
The lower right image is an example of a parabolic soup cantenna constructed using an old satellite dish. No figures seem to be cited, though the construction is worth noting. We’ve had success with old satellite dishes in the past. The upper right and lower left pictures are scanning Cantennas. They use servos to seek out stronger connections by moving and checking the signal strength. Below is an in line video of the lower left cantenna while scanning. Maybe you want to know How to build a tin can waveguide WiFi Antenna. All the instructions are provided complete with a rough cost break down, and the site has a calculator to determine cut off frequencies given a can’s diameter.