Five bars on my phone in an area with poor cellular coverage

I live in an area with poor cellular coverage; mountainous terrain, very low population density and at least 50 miles away from the next big town. So you can imagine my delight when I noticed that my AT&T BlackBerry had full signal at work, after having gotten used to no more than two of the five bars.

As much as I would wish to thank AT&T. They deserve no credit because as soon as I left the office building my signal strength was back to normal; two bars. Rather the organization I work for had installed a a device that miraculously improves the signal strength in all the buildings.

My first thought was that they had installed a femtocell; the AT&T 3G MicroCell which was launched in late March 2010. But I have not seen any devices and people at the office say that there were antennas installed on the roofs of all the buildings. So it must be a device that amplifies the existing signal rather than offload the AT&T voice and data traffic through the Internet. But the antenna do not look like any of the advertised devices that boost the signal strength.

As soon as I find out what technology and devices are being used I will let you know. For now I am content with having five bars on my phone in the office.