The cell carrier Telstra in Australia has developed a sophisticated program that crawls the logs of all performance problems recorded on the Telstra network in search of issues. When it finds one, it's generally either caused internally by the infrastructure due to aging cables or a bad connection or it's an external source that happens to be causing radio interference in the same frequency range that Telstra's network operates.
In a recent example, the software robot identified a location in north-east Victoria, Australia, where the performance issue logs showed a problem with the noise level in the cellular uplink connections. The network operations team investigated using directional yagi antennas to zero-in on the origin of the interference. In an unusual twist, it turned out that the interfering signal was being generated by a beer fridge in someone's garage! The motor in the fridge had an electrical issue which caused it to generate noise on the same 800 (850) MHz frequency used by cell phones. The interference was so bad that it affected multiple surrounding neighborhoods.
Typically, the cause of network interference can be traced back to any number of things including television antenna amplifiers, certain types of metal & plastic welding equipment, and other electrical equipment. When the network operations team identifies the source of the interference, they ask the owners to turn off the equipment, which most do. However, if the owner is less then cooperative, the carrier will report the matter to the Australian Communications and Media Authority (ACMA), which is similar to our FCC, who can impose fines for operating interfering equipment.
One answer that was not immediately available was what exactly that poor gentleman did with all of his beer. From Slashdot