This is a quick and easy way to get more range with no cost at all. The video shows how a little tinfoil fashioned into a “Windsurfer” parabola can increase your signal strength several decibels.

The parabola diagram and instructions are available at http://www.freeantennas.com/projects/template2/index.html

Just in case the link is no available, here is the diagram (click for bigger version, or right-click and save image).

The instructions are very simple:
1. Download Template
2. Open in a image editor application and resize as desired. Ensure that you keep the square on the diagram square.
3. Print image on business card stock or acetate (document protector).
4. Cut it out and open the six slots with scissors or an X-Acto knife.
5. Glue tin foil to the back side of the reflector surface
6. Assemble by placing the six tabs in the six slots.

If printed at the download size you will see about 9 dBi of gain. If you double the size of the image before you print it you will see about 12 dBi of gain. If you place two reflectors on an AP with two antennas you will see an additional increase in performance.