Among the most potentially damaging weapons of electromagnetic warfare are RF, or radio frequency systems. Also known as directed-energy weapons, these use electromagnetic energy on specific frequencies to disable electronic systems. There exist means to protect against directed-energy weapons; aside from "hardening" computer systems, protection is possible through the employment of electronic RF detection equipment, which operates on a principle similar to that of radar.
In the modern world of sophisticated, computerized fighter jets, the missile systems of one fighter aircraft can only "lock on" and fire on an enemy craft if the enemy has his radar systems activated. The same electronic radio-frequency system that allows a plane to navigate also makes it capable of being tracked electronically across the sky. Similarly, that which makes RF weaponry so potentially threatening—the fact that they can disable flight systems by interfering with vital frequencies on the electromagnetic spectrum—also makes them detectable.
Given the fact that Soviet and Russian technicians have reportedly developed RF weaponry, it is assumed that technicians working for the United States Department of Defense have created RF detection equipment at least as sophisticated. At a much lower end are civilian and consumer versions of computerized RF detection equipment, retailing for a few hundred or thousand dollars. A January 2003 article in the Wall Street Journal described a pocket wireless system called Spotme that could read electronic badges on guests at a party and provide the user with other guest's names, photographs, and contact information. For security purposes, there are RF detection consoles that operate across a wide frequency spectrum to search out and identify potentially harmful RF sources.
█ FURTHER READING:
Fund, John. "In the Fray: People Spotters—European Gizmo Tells Who's Who." Wall Street Journal. (January 23,2003): D8.
Torregrosa-Penalva, German, et al. "Microwave Temperature Compensated Detector Design for Wide Dynamic Range Applications." Microwave Journal 44, no. 5 (May 2001): 336–346.