A system and method of detecting, locating, geolocating and providing diagnostics on electronic devices includes use of emission detection apparatus, information collected over a network and template containing emission signatures. Collected unintended emissions are compared to an emission signature in the template preferably constructed from the information collected on the network. Using the known location of the electronic device, the emissions measurement device is then used to detect and identify other devices in the vicinity of the electronic device that is connected to the network. The emission detection apparatus includes a high sensitivity receiver for receiving and analyzing electronic emissions. The network collection apparatus could be any software manifestation known in the art for collecting information about a device such as a cookie or online fingerprinting or a hardware based collection mechanism.