There are a lot of tricks out there on the internet that describe devices you can build to increase the range of your wi-fi router. But there's another solution: just buy another antenna. Most wi-fi routers have removable antennas. And a very easy way to increase the range of your wi-fi signal is to take off the cheap antenna it comes with and replace it with a better antenna. There are a lot of good models out there in the $15 - $20 range. It's not as cheap as building something yourself, but it is a far more reliable way to increase the range of your wi-fi antenna