Dry jammers can be as smart as mobile phones

NEW YORK – A cafe customer who is fed up with cell phone chatter sits in a bubble of blissful silence as patrons nearby puzzle over dead handsets.

A man tries to take a secret snapshot with his camera phone, but only gets a blank screen.

A priest gives his church a new energy – electromagnetic – to keep his sermons calm and free from beeps, chirps and ringtones.

These are glimpses of a war of devices that play quietly around the world.

While millions welcome the freedom of mobile communication, some people and companies are pushing against the current. They fight technology with technology and use detectors, cell phone jammer and other things to protect privacy, security and sometimes mental health.

Cell phone interference is prohibited in the United States, but with pocket-sized jammers sold online by foreign companies and even on eBay, and with such devices already by the military and government, the wireless struggle is already there.

“It’s like a battle between radar detectors and radar cannons. It’s escalating all the time,” said Jeff Kagan, an independent Atlanta-based telecommunications analyst. He said the need for such devices was triggered by the “double-edged sword of technology”.

“The inventor of the cell phone never thought that people would use it all the time and affect other people’s privacy,” he said. “The inventor of the camera phone never thought about being used in changing rooms and other unsuitable places.”

Interfering with a cell phone, essentially a radio, is relatively easy.

Jammers typically interfere with communication between handsets and cell towers by flooding an area with interference or selectively blocking signals by transmitting on the same frequencies that phones use.

Some jammers may need to be as smart as a cell phone trying to increase performance or hop on other radio channels to avoid interference.

Depending on their strength, jammers can interfere with communication within a few meters or over several kilometers.

Commercial jammers have been sold overseas for years, and some internet posts even include instructions for building homemade models.

The Federal Communications Commission prohibits people in the United States from building, selling, operating, or importing radio interference devices.

Persons who violate this provision of a 70-year-old communications law face a prison sentence of up to one year and a fine of $ 11,000 per violation.

However, FCC officials said they received very few complaints about jammed cell phones and have never acted against anyone because of this injury.

Jammer experts claim that individuals use low-power devices that are not afraid of reprisals because it is difficult, if not impossible, for a caller to distinguish between a jammed signal and a normal dead zone on a cell phone.

Even so, U.S. law restricts the use of jammers and restricts their distribution to consumers, said analyst Kagan.

The wireless industry says that jamming devices endanger the public.

“One hundred and fifty million Americans are dependent on cell phones. If these phones are blocked, doctors may miss calls to hospitals or parents may miss emergency calls from babysitters,” said Travis Larson, spokesman for the Cellular Telecommunications and Internet Association.

Larson said in order to reduce the nuisance of cell phone use, customers should use their “mute button, volume control, vibrate mode, voicemail and an on / off button” when appropriate.

He said disrupting a particular area where silence is expected, such as a movie theater, is still a risk despite warning signs.

“Jammers could penetrate other neighboring frequency bands and block radio signals for public security used by police officers and firefighters,” he said.

But safety concerns, courtesy suggestions, and the law didn’t stop people from buying jammers.

The British company Global Gadget UK sells a range of troubleshooting products to customers in other countries, including a portable jammer disguised as a cell phone that can disrupt cellular communications up to 30 meters away from the user.

“They will be able to silence those anti – social types who insist on their mobiles