Local Police Want Right to Jam Wireless Signals
Sunday, February 1, 2009
As President Obama's motorcade rolled down Pennsylvania Avenue on Inauguration Day, federal authorities deployed a closely held law enforcement tool: equipment that can jam cellphones and other wireless devices to foil remote-controlled bombs, sources said.
It is an increasingly common technology, with federal agencies expanding its use as state and local agencies are pushing for permission to do the same. Police and others say it could stop terrorists from coordinating during an attack, prevent suspects from erasing evidence on wireless devices, simplify arrests and keep inmates from using contraband phones.
But jamming remains strictly illegal for state and local agencies. Federal officials barely acknowledge that they use it inside the United States, and the few federal agencies that can jam signals usually must seek a legal waiver first.
The quest to expand the technology has invigorated a debate about how widely jamming should be allowed and whether its value as a common crime-fighting strategy outweighs its downsides, including restricting the constant access to the airwaves that Americans have come to expect.
"Jamming is a blunt instrument," said Joe Farren, vice president of government affairs for the Cellular Telecommunications Industry Association. He and others pointed out that when authorities disable wireless service, whether during a terrorist attack or inside a prison, that action can also stop the calls that could help in an emergency. During November's raids in Mumbai, for example, citizens relied on cellphones to direct police to the assailants.
Propelled by the military's experience with roadside bombs in Iraq and Afghanistan, jamming technology has evolved to counter bombs triggered by cellphones, garage openers, remote controls for toy cars or other devices that emit radio signals. Federal authorities rank improvised bombs, which are cheap and adaptable, as one of the greatest terrorist threats to the West.
On Inauguration Day, federal authorities were authorized to jam signals at some locations in downtown Washington, according to current and former federal officials. The Secret Service and other officials declined to provide specific details, some of which are classified.
Most of the nearly 2 million people attending the swearing-in and along the parade route would have been oblivious to any unusual disruption.
"Chances are, you wouldn't even notice it was there," said Howard Melamed, an executive with CellAntenna Corp., a small Coral Springs, Fla., company that produces jamming equipment. If someone in the crowd was on a call, they might have confused the jamming with a dropped signal. "Your phone may go off network," he said. In other cases, "it may never signal, if it's a quick interruption."
Industry officials said that radio-jammers work in several ways: They can send a barrage of energy that drowns out signals across multiple bands or produce a surge of energy on a particular frequency. In other instances, the devices detect and disrupt a suspicious signal, a technique known as "scan and jam."
Some private citizens, hoping to eliminate cellphone calls in restaurants, churches or theaters, have tapped into an underground market of jamming equipment that has trickled into the United States. But that, too, is illegal under the 70-year-old federal telecommunications act, which bans jamming commercial radio signals. The Federal Communications Commission has begun to crack down on private use, which is punishable by an $11,000 fine.
The U.S. military is capable of shutting down communications across a wide area and has done so overseas, including when it has conducted raids to capture suspects. To counter explosives, devices can be set to jam signals for a distance of 50 to 500 meters, for example, or enough to allow a car to pass out of the blast zone of a small bomb.