GPS jamming is a continuing threat. A detailed understanding of how the available jammers work is necessary to judge their effectiveness and limitations. A team of researchers from Cornell University and the University of Texas at Austin reports on their analyses of the signal properties of 18 commercially available GPS jammers.

　　Many more likely go undetected each day. In 2009, outages of a Federal Aviation Administration reference receiver at Newark Liberty International Airport close to the New Jersey Turnpike were traced to a $33, 200 milliwatt GPS jammer in a truck that passed the airport each day. And in Germany, some truck drivers have been using jammers to evade the country’s GPS-based road-toll system.

　　The U.S. and some foreign governments have enacted laws to prohibit the importation, marketing, sale or operation of these so-called personal privacy devices. Nevertheless, a certain number of jammers are in the hands of individuals around the world and they continue to be available from manufacturers and suppliers in certain countries. So, GPS jamming is a continuing threat both at home and abroad and a detailed understanding of how the available jammers work is necessary to judge their effectiveness and limitations. This information will also help in developing countermeasures that could be incorporated into GPS receivers to limit the impact of phone jammer.

　　Jammers constitute an enemy force, and as the Chinese General Sun Tzu stated in the Art of War more than 2,000 years ago, battles will be won by knowing your enemy.

　　We all know that our wi-fi enabled devices can occasionally just lose a signal. Chances are, that’s a result of an unintentional interruption in communication. It doesn’t necessarily mean that someone’s lurking nearby, purposely disrupting the device and causing you to lose your signal.

　　However, when a cell phone jammer is being used, it can block any device within a certain range from connecting and communicating. Whatever device is using the same frequency, the jammer can prevent any incoming or outgoing communication.

　　Jammers are a direct safety threat. It’s obvious that blocking someone from using their cell phone for communication would cause quite an issue. However, most jammers aren’t sophisticated enough to differentiate which signals they’re blocking, therefore causing much more serious issues.

　　Using a transmitter to affect simple communication might seem like a prank or a silly joke, but these devices could also impede nearby emergency communication. They could also affect a wider range of communication, causing issues on many levels.

　　Jamming a GPS signal could result in someone not being able to dial 911, or the emergency services being unable to find that person.

　　While there’s no simple way for the average human to block a jammer, you can detect whether or not one is being used on your signal. You may be able to find where the transmitter is located, and then turn it off. Of course, this probably isn’t very safe, depending on who is using the jammer especially since they’re engaging in criminal activity.

　　Maybe if you’re an experienced hacker then yes, you may be able to jam the jammers gps. But that would also involve illegally blocking a signal and making you just as culpable as the one doing the first jamming. Then you’d be guilty as well, and that all sounds like a terrible idea.

　　The way we communicate has changed a lot over the years. From handwritten letters to electronic e-mails to smoke signals and text messages, the way we exchange messages have developed so much thanks to the help of technology.

　　Probably one of the most ground-breaking inventions in the communications field is when the wireless signal transmission was discovered. As expected, this development came with a pair—in this case, the science of signal jamming. To explain it simply, signal jamming happens when a device’s frequency collides with another signal of the same frequency but at higher power. When this happens, the receiving device will not be able to process signals properly and stop functioning correctly.

　　It is also not uncommon for signal jammers gps to be used in situations like VIP transport and transfer. Rather than blocking the transfer of communication signals, however, specific signal jamming devices are also used to render a certain area radius safe from the detonation of bombs, particularly improvised explosive devices. These types of signal jammers work by countering the signals that can otherwise set off explosives.

　　Personal Uses jammers

　　Signal jammer devices used for WiFi are usually employed by companies and organizations that need extra protection against data theft. Many companies opt to have it to prevent information leaks that can cause expensive data loss.

　　Cell phone jammers are a type of jamming device that blocks the signals that smartphones receive. It can help keep individuals safe from pesky calls and usually work only on limited spaces. There are even portable models of such devices that are specifically designed to be light so that a person can easily take it with them as they move.

　　Signal Jamming may have a shaky start in history but the method does prove itself useful for modern situations too. Granted that personal use of it is commonly not allowed by most governments, it pays to know that it can also be used for other meaningful purposes as well.

　　Signal Jamming: A Brief History

　　The act of jamming signals was widely used during World War II and the Cold War. Besides using it to disrupt messages from reaching their intended countries, jamming of broadcast stations was also propagated back then. During the Cold War period, the broadcasters from the Soviet and the West even battled in a “power race” in which the mobile phone jammer worked to increase their transmission powers.

　　The situation started changing at the end of the Cold War. As the Soviet Union fell from power, the Western forces gained more traction and control over innovation and technology in general. However, with no need for “signal battles,” signal jamming was also classified as an illegal act among many countries, with the exception being for government, military, and defense applications.

　　Electrical Jamming

　　A strategy wherein jammers send interfering and highly-concentrated signals to radar or receiver either through noise or repeater techniques. Noise jamming is divided into three types namely spot, sweep, and barrage.

　　Blocking of Cellphone Usage in Schools or Prisons

　　Signal Jamming devices are very popularly used in environments where mobile phone use is not allowed. A school is a place where they are commonly used since they help take out the distraction that smartphones pose on education. A cellphone blocker from The Signal Jammer is a good option, and can also be used for either personal (as long as it’s legal) and organizational purposes. Prison is another example where it is not uncommon for inmates to successfully smuggle a smartphone despite restrictions. Signal Jamming is used in this situation as a safety precaution since it works to block off all possibility of communications from inside the prison to the outside world.

　　Privacy Purposes

　　GPS jammers are types of signal jamming devices that work by blocking possible GPS monitoring on devices or vehicles. They can also be paired with a GPS Tracker Detector which can be used to spot bugs planted on a person or their vehicle.

　　India NAGPUR: Sadar police on Wednesday arrested one Deepak Ledwani, a resident of Jaripatka, for running away with a signal jammer put on his four-wheeler by Nagpur traffic police.

　　Police constable Sayed Ahmed attached with Sadar traffic zone on Tuesday put a tyre jammer on a wrongly parked car bearing number MH-31-FA-3911 on Mount Road, to ensure the driver was forced to pay a fine for traffic violation.

　　When Ledwani returned to his vehicle, he saw the jammer and decided to take matters into his own hand. He allegedly unscrewed the wheel along with the jammer and put in the back of his vehicle. He replaced the wheel with a spare and drove off.

　　Later, Sayed lodged a complaint of theft against the car owner and on Wednesday the police traced the owner and arrested Deepak Ledwani. The police produced him before the court which granted him bail on deposit of personal bond of Rs15,000.

　　Meanwhile, Ledwani has been fined Rs3,800 by the traffic police for keeping the jammer with him from the day of the incident till Wednesday. It is learnt that he did not pay the fine. There is a provision to levy a fine of Rs50 per hour on the driver who does not approach the vehicle after seeing the jammer on his car. If a vehicle is parked in a no-parking area, the traffic police can impose a fine of Rs250.

　　To prevent the car from being tracked, you can use a portable handheld GPS jammers, carry a car charger, and provide wireless battery life for your jammer without worrying about the battery. Portable design is convenient for your travel and you can use it anywhere.

　　The Khadak police have launched an investigation after a scooter, which was impounded and fixed by a jammer by traffic constables on Tuesday night and parked alongside the Shivaji Road, was found missing on Wednesday morning.

　　The police suspected that the owner of the two-wheeler might have taken away his vehicle, along with the cell phone jammer.

　　However, till Thursday night, neither the vehicle nor its owners could be traced, the police said.

　　“Based on the vehicle’s registration number and information from the Regional Transport Office (RTO), our team went to the owner’s residence. However, the owner of the vehicle was not present in the residents,” a Khadak police officer said on Thursday.

　　On Tuesday night, two traffic constables had intercepted a scooter rider for driving on the wrong side of the road. The constables suspected that the scooter rider was an inebriated condition. They fixed a jammer on his two-wheeler after parking it alongside the road, the police said.

　　Early on Wednesday morning, when the police reached the spot, they found that the vehicle was missing and the GPS jammers was also nowhere to be seen.

　　The police have registered a case of theft of a jammer worth Rs2,500 and offences punishable under Motor Vehicle Act against an unknown person.

　　All states and Union territories can now secure Central funds for buying body worn cameras for their prison staff to capture incidents of indiscipline and violence in jails and also for installing technology-based mobile phone jammer solutions to block unauthorised use of cell-phones by the inmates.

　　As part of the modernisation of prisons project, the ministry of home affairs shall offer grants in aid to the states for a period of five years starting with the current financial year, for deploying modern-day security equipment in prisons for their enhanced security and also to facilitate the task of reformation of prisoners through correctional administration.

　　As per guidelines for implementation of the modernisation of prisons project, shared recently by the home ministry with the chief secretaries or administrators of all states and UTs, the funds can be released by MHA for upgrading all categories of jails like Central jails, district jails, sub-jails, women ’s jails, open jails and special jails. The funds shall be released for purposes such as creating a video conference infrastructure to enable online trial of high-risk prisoners; body worn cameras to keep a vigil on conduct of the jail staff as well as activities of prisoners; modern gadgets for access control; mobile phone jamming solutions to restrict use of cell-phone smuggled in by inmates; and correctional programmes for prisoners, including their counselling, therapy and vocational training. The funds may also be utilised for setting up small industrial units in jails which will provide opportunity of labour to the inmates and generate revenue for jails, besides providing on-the-job vocational training and skills.

　　While the role of the MHA would include developing overall strategy for modernisation of prisons and monitoring and evaluating the project, the states will be required to procure equipment, update database of prisoners, furnish periodic funds utilisation reports and maintain the procured jammers gps equipment.

　　Funds under the prisons modernisation project will be released by MHA each year during the period from 2021-22 to 2025-26, on the recommendation of a steering committee. The release of funds in subsequent years will be based on utilisation certificates furnished by the states in respect of funds released during the previous years.

　　Electronically speaking,cell phone jammer 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 GPS jammers range with just a few steps.

　　Jamming devices overpower the cell phone by transmitting a signal on the same frequency and at a high enough power that the two signals collide and cancel each other out. Cell phones are designed to add power if they experience low-level interference, so the cell phone jammer must recognize and match the power increase from the phone.

　　Cell phones are full-duplex devices, which means they use two separate frequencies, one for talking and one for listening simultaneously. Some jammers block only one of the frequencies used by cell phones, which has the effect of blocking both. The phone is tricked into thinking there is no service because it can receive only one of the frequencies.

　　Less complex devices block only one group of frequencies, while sophisticated jammers can block several types of networks at once to head off dual-mode or tri-mode phones that automatically switch among different network types to find an open signal. Some of the high-end devices block all frequencies at once, and others can be tuned to specific frequencies.

　　To jam a cell phone, all you need is a device that broadcasts on the correct frequencies. Although different cellular systems process signals differently, all cell-phone networks use radio signals that can be interrupted. GSM, used in digital cellular and PCS-based systems, operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the 1900-MHz (sometimes referred to as 1.9-GHz) band in the United States. Jammers can broadcast on any frequency and are effective against AMPS, CDMA, TDMA, GSM, PCS, DCS, iDEN and Nextel systems. Old-fashioned analog cell phones and today's digital devices are equally susceptible to jamming.

　　The actual range of the jammer depends on its power and the local environment, which may include hills or walls of a building that block the jamming signal. Low-powered GPS jammers block calls in a range of about 30 feet (9 m). Higher-powered units create a cell-free zone as large as a football field. Units used by law enforcement can shut down service up to 1 mile (1.6 km) from the device.

　　Cell phones are everywhere these days. According to the Cellular Telecommunications and Internet Association, almost 195 million people in the United States had cell-phone service in October 2005. And cell phones are even more ubiquitous in Europe.

　　Unfortunately, restaurants, movie theaters, concerts, shopping malls and churches all suffer from the spread of cell phone jammer because not all cell-phone users know when to stop talking. Who hasn't seethed through one side of a conversation about an incredibly personal situation as the talker shares intimate details with his friend as well as everyone else in the area?

　　While most of us just grumble and move on, some people are actually going to extremes to retaliate. Cell phones are basically handheld two-way radios. And like any radio, the signal can be disrupted, or jammed.

　　Disrupting a cell phone is the same as jamming any other type of radio communication. A cell phone works by communicating with its service network through a cell tower or base station. Cell towers divide a city into small areas, or cells. As a cell-phone user drives down the street, the signal is handed from tower to tower.

　　A jamming device transmits on the same radio frequencies as the cell phone, disrupting the communication between the phone and the cell-phone base station in the tower.

　　It's a called a denial-of-service attack. The GPS jammers denies service of the radio spectrum to the cell-phone users within range of the jamming device.