DIY 2G/3G/4G Wireless Cell Phone Signal Booster
DIY 2G/3G/4G wireless cell phone signal booster is a home-brew booster which uses common household items. This DIY can improve the signal of cell phone signal inside your house, from 1 bar to full. According to the author of the project.
I guess this would make sense to at least try if you live out in the country and your cell phone signal is poor. I know you can buy 3g signal boosters but I have heard they are expensive.
Read the comments on this one too. A lot of wise folk always give their 2 cents worth and usually ends up making the whole project better.