Here at the amazing HAR2009 hacker conference + camp, I have the pleasure of operating a camp-wide GSM network.
Under license of the Dutch regulatory authority, we operate two BTS with two TRX each, forming the network 204-42. The BTS are positioned on the top of a hill, with the antennas mounted back to back on a tree, each covering about half of the HAR2009 camp site. Every transceiver runs at 100mW transmit power, which is the maximum output as per our license.
From that tree, we run AC power and a single E1 line down to the GSM tent, where it runs into the Linux PC that runs our OpenBSC software.
If you register first to the network, your phone will receive a single SMS and then get kicked off the network. Inside the SMS we send your IMSI and an authentication token, which you have to use on the HAR2009 GSM registry. After registering at this website, the SIM will be permitted onto our network for regular voice call and SMS service.
Right now, as you can see on our phone book, we have 391 authorized subscribers (out of a total of 1029 different IMSI's that ever tried to log onto our network)
The coverage of the network is good, we have only very few spots without signal reception.
OpenBSC has proven to work quite stable. We have the occasional segfault every 3-4 hours, but I'm at it, debugging.
Thanks to everyone who helped to make this a success, especially Stichting Hxx for obtaining the license and Daniel, Stefan and Jan for helping me with operation and debugging of the network.