hedgemage writes "I work at a retirement home and we have trouble with the cell phones that our nursing and maintenance staff use. The problem is that our nursing home area is built into a lower level that was originally constructed as a fallout shelter in 1960. There's a lot of solid concrete in the walls and ceiling. We have paid out tens of thousands to try and get an on-site mobile to work using NEC Dterm PSII phones, but they have proven absolutely unreliable (not just in the bomb shelter but throughout the campus) and the only solution our telecom provider has is to install several thousand dollars more in transcievers. If we could use ordinary cell phones, it would be ideal for everyone. Is there an off-the-shelf solution that could boost regular cellular signals in our bomb shelter?"