Inside Cell Phone Jammers

Electronically speaking, cell-phone jammers are very basic
devices. The simplest just have an on/off switch and a light
that indicates it's on. More complex devices have switches to
activate jamming at different frequencies. Components of
a jammer include:

Antenna
Every jamming device has an antenna to send the signal. Some
are contained within an electrical cabinet. On stronger
devices, antennas are external to provide longer range and
may be tuned for individual frequencies.

Circuitry
The main electronic components of a jammer are:

* Voltage-controlled oscillator - Generates the radio
signal that will interfere with the cell phone signal.
* Tuning circuit - Controls the frequency at which the
jammer broadcasts its signal by sending a particular voltage
to the oscillator.
* Noise generator - Produces random electronic output in
a specified frequency range to jam the cell-phone network
signal (part of the tuning circuit).
* RF amplification (gain stage) - Boosts the power of the
radio frequency output to high enough levels to jam a signal.

Power supply
Smaller jamming devices are battery operated. Some look like
cell phone and use cell-phone batteries. Stronger devices can
be plugged into a standard outlet or wired into a vehicle's
electrical system.

* Check your phone - If the battery on your phone is
okay, and you'd like to continue your conversation, try
walking away from the area. You may be able to get out of the
jammer's range with just a few steps.

Cell Phone Jamming Legal Issues

In the United States, United Kingdom, Australia and many
other countries, blocking cell-phone services (as well as any
other electronic transmissions) is against the law. In the
United States, cell-phone jamming is covered under the
Communications Act of 1934, which prohibits people from
"willfully or maliciously interfering with the radio
communications of any station licensed or authorized" to
operate. In fact, the "manufacture, importation, sale or
offer for sale, including advertising, of devices designed to
block or jam wireless transmissions is prohibited" as well.

Jamming is seen as property theft, because a private company
has purchased the rights to the radio spectrum, and jamming
the spectrum is akin to stealing the property the company has
purchased. It also represents a safety hazard because jamming
blocks all calls in the area, not just the annoying ones.
Jamming a signal could block the call of a babysitter
frantically trying to contact a parent or a someone trying to
call for an ambulance.

The Federal Communications Commission is charged with
enforcing jamming laws. However, the agency has not yet
prosecuted anyone for cell-phone jamming. Under the U.S.
rules, fines for a first offense ca­n range as high as
$11,000 for each violation or imprisonment for up to one
year, and the device used may also be seized and forfeited to
the government.

In most countries, it is illegal for private citizens to jam
cell-phone transmission, but some countries are allowing
businesses and government organizations to install jammers in
areas where cell-phone use is seen as a public nuisance.
In December 2004, France legalized cell-phone jammers in
movie theaters, concert halls and other places with
performances. France is finalizing technology that will let
calls to emergency services go through. India has installed
jammers in parliament and some prisons. It has been reported
that universities in Italy have adopted the technology to
prevent cheating. Students were taking photos of tests with
their camera phones and sending them to classmates.

With phones ringing in movies, weddings and classrooms, it's
no wonder people want to tone down the intrusion. So what
legally can be done to stop annoying cell-phone use?