With $500 (about £310) and a trip to the hardware store, saboteurs can build a device capable of remotely disrupting computers, automobiles, medical equipment and nearly anything else dependant on electronics, according to a California engineer who demonstrated a homebrew computer death-ray at the InfowarCon '99 conference in Washington, D.C. Wednesday.
Former Navy engineer David Schriner showed off an unwieldy device constructed from a parabolic reflector, a horn antenna and two automotive ignition coils, which he aimed at two personal computers about 20 feet away. When an assistant activated the Rube Goldberg contraption by connecting it to a car battery, the conference room filled with a loud buzzing from the PA system and a PowerPoint presentation on the projection screen flickered and scattered. One of the computers instantly dropped out of its screen saver.
When the device was switched off, both PCs were frozen, and wouldn't respond to keyboard input.
The effects of High Energy Radio Frequency (HERF) emissions on electronics are well known among engineers, and info-warriors have expressed concern that adversarial nations may someday include computer-killing devices in their arsenals. Military aircraft are built with hardened electronics designed to survive the electromagnetic pulse created by a nuclear detonation. Schriner theorised that a single nuclear weapon designed specifically for the purpose "would probably take out all of the electronics on the East Coast".
But Schriner, who has devoted his research to small-scale electronic warfare, said the demonstration was intended as a "wake up call" to show that even low-budget saboteurs can create viable electronic weapons. "We bought the car battery at Wal-Mart yesterday," said Schriner. "It's all stuff you can buy at the hardware store."
The HERF gun is not particularly high-tech, either. The device uses technology dating back to Tesla, essentially pushing a 20-megawatt burst of undisciplined radio noise through an antenna. The energy is enough to interfere with sensitive computer components nearby, creating unpredictable results ranging from minor anomalous behavior to complete burnout. Schriner said he's built larger HERF guns capable of crashing computers and disabling automobiles at a range of 100 feet, with a cost as low as $300.
Jonathan Lemkin, a screenwriter working on an infowar script for Paramount, was particularly impressed with the dramatic display and menacing hardware. "That's definitely going in the movie," he said.
The computers targeted in today's demonstration worked fine after rebooting, and Schriner said permanent damage is uncommon. "But if that happens to be a computer in a tank, or in a piece of medical equipment, how long does it take to reboot?... By that time you could be dead."
Conference organiser and infowar author Winn Schwartau said Wednesday's demonstration validates a threat he first tried to warn Congress about in 1991.
"They asked if I thought they should add HERF guns to the Brady [weapons-control] Bill ," Schwartau recalls.