Police in Taiwan recently used handheld spectrum analyzers to catch at least three people suspected of cheating on an exam by monitoring for mobile phone signals. Officers monitored an exam in south Taiwan for prospective government workers, said senior company engineer Lai Cheng-heng. The devices checked for signals from pagers or mobile phones near the test site. Those sitting for the exam are supposed to shut off their mobile phones to stop test answers from reaching them via calls, text messages or vibrations.
Spectrum analyzers cannot conclusively identify specific phone users, he said, but they can narrow down the area from which a call was made. Such data is useful in conjunction with other evidence of cheating. An officer who followed up the exam for a range of government jobs said he was unsure how many people would be formally accused of cheating. But he said the "effectiveness" of the analyzers was "very high."http://www.techworld.com.au/article/373172/spectrum_analyzer_catches_exam_cheats_taiwan/?fp=2&fpid=1&rid=1