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It's amazing what a few sheets of tinfoil can do for the strength of your wireless signal. As shown above, by carefully folding tinfoil into a parabola, you can boost your wireless strength tremendously. The fellas in the video saw gains from 82% to just under 100%, though I only saw boosts of around five percent, so your mileage may vary. This project should only take about three minutes and will hopefully leave you with impressive results. If you don't want to attach unsightly parabolic boosters and you're using the same basic router as the fellas in the video, you can also upgrade your firmware to DD-WRT—a free hack that will turn your $60 router into a $600 router and allow you to boost your Wi-Fi signal from your router's control panel.
Deep Dish Cylindrical Parabolic Template [FreeAntennas.Com]