A French father is facing jail time and a hefty fine for using a signal jammer to block his children from going online and affecting others in a nearby town.

Starting at midnight and ending at 3am every week, the French town of Messanges found their mobile phones and internet service no longer functioning.

A mobile operator reported the problem to the Agency Nationale des Frequencies (ANFR), the public agency responsible for managing the radio spectrum in France, and it was determined that someone was using a signal jammer to block radio frequencies in the town.

A signal jammer is a device that transmits radio waves at the same frequency as mobile devices to prevent them from connecting to cell towers and receiving legitimate signals.

A report from the ANFR explains that a technician tracked the jamming signal to a house in a neighboring town, where the homeowner admitted to buying the mobile jammers online and using it to force his teenage children offline.

“The reason is disturbingly simple: the jammer was installed by the head of the family in order to prevent his children from surfing the internet on their smartphones before bedtime! His children have literally become addicted to social networks and other apps, especially since the quarantine due to the Covid-19 pandemic,” the ANFR explains in the report.

“After consulting Internet forums, the father decided that a jammer was the best solution to stop these excesses!”

While the father’s intention was not to disrupt the internet for the entire town, using a jamming device is illegal in France and punishable by a fine of up to €30,000 and six months in prison.

Similarly, using a jammer in the United States is illegal and can result in prison and hefty fines.

“The use or sale of jammers in the United States may be subject to hefty fines, confiscation of illegal devices, and criminal sanctions including imprisonment,” the FCC’s enforcement alert on jamming explains.

Georgia's attorney general wants a federal agency to lift its ban on mobile signal jammer that bars state officials from using the devices to block contraband cell phones in jails and prisons.

The Federal Communications Commission currently bars cell phone "signal blocker" within prisons and jails, a prohibition Georgia Attorney General Chris Carr's office said extends to state and local governments. Carr made his request to reconsider the prohibition in a Tuesday letter to FCC Chairwoman Jessica Rosenworcel.

According to data included in the letter, contraband cell phones frequently make their way into jails and prisons, creating dangerous situations for inmates and correctional officers. Georgia officials confiscated 8,074 contraband cell phones in 2023 and 5,482 to date in 2024.

"The easiest way to protect the public from the harms caused by contraband cell phones is to allow for the use of cell phone jamming technology in prisons and jails, but the FCC continues to block our efforts," Carr said in a Tuesday statement.

"This outdated guidance limits legitimate law enforcement tools, presents dangerous conditions for correctional officers, and allows for the escalation of criminal networks both inside and outside prison walls," Carr added. "We're committed to combatting violent crime wherever it occurs, which is why we continue to call on the federal government to remove this substantial barrier to public safety."

In March, Georgia officials announced the results of "Operation Skyhawk," a months-long investigation into contraband at Georgia Department of Corrections facilities.

Authorities seized 273 contraband cell phones in facilities and arrested 150 suspects, including eight GDC employees who were immediately terminated. Bad actors used drones to help introduce contraband into the facilities.

"There are hundreds of examples from across the country of how a contraband cell phone in the hands of an inmate can be used as a deadly weapon and gives them the ability to continue their criminal enterprise," Georgia Department of Corrections Commissioner Tyrone Oliver said in a release.

"We are incensed by the length these individuals go to in continuing those activities and endangering the public," Oliver added. "As attempts to infiltrate our facilities with contraband cell phones evolve, access to jamming technology is paramount in our efforts to combat those attempts."

When asked whether he had a position on this request, a spokesperson for U.S. Sen. Jon Ossoff, D-Georgia, pointed to legislation he sponsored with U.S. Sen. Chuck Grassley, R-Iowa, to crack down on contraband in federal prisons.

In 2022, Ossoff led a 10-month-long bipartisan investigation into misconduct at U.S. Penitentiary Atlanta, now FCI Atlanta. The investigation's findings revealed the need to eliminate illegal cell phones in the facility.

Detecting whether a cell phone jammer is being used can be challenging, but there are several signs and methods you can use to identify potential jamming activity:

Signs of Cell Phone Jamming

Sudden Signal Loss: If multiple cell phones in the same area suddenly lose their signal and cannot connect to the network, this could indicate the presence of a jammer.

Poor Call Quality: Frequent call drops, inability to make or receive calls, or severe degradation in call quality in an area where you usually have good reception can be a sign of jamming.

Interrupted Data Services: Slow or nonfunctional data services (such as internet browsing, messaging apps, and email) in areas where they typically work well.

No WiFi Connectivity: If WiFi networks are also affected and users are unable to connect, this could be due to a jammer targeting multiple frequencies.

Consistent Pattern: If the signal issues occur at specific times or locations consistently, it may suggest intentional jamming.

Methods to Detect Cell Phone Jamming

Check Multiple Devices: Verify the signal on multiple cell phones from different carriers. If all devices show similar issues, it's likely not a carrierspecific problem.

Use Signal Detection Apps: There are apps available that can analyze the signal strength and quality. Sudden drops or patterns in the signal may indicate jamming.

Professional Signal Detectors: Invest in a professional signal detector or spectrum analyzer. These devices can detect jamming signals by analyzing the radio frequency spectrum and identifying unusual or strong signals in the cellular bands.

Contact Your Carrier: Reach out to your mobile carrier's customer service. They may have tools to detect jamming activities and can investigate the issue.

Listen for Interference: Some jammers may emit a faint buzzing or humming noise, although this is not always the case.

Professional Detection Equipment

If you suspect persistent jamming and need a reliable method to detect it, consider the following professional equipment:

RF Detectors: These devices can detect a wide range of frequencies and are useful for identifying jamming signals.

Spectrum Analyzers: These provide a visual representation of the frequency spectrum, allowing you to see the presence of jamming signals.

Cell Phone Signal Monitoring Systems: Specialized systems designed to monitor and detect disruptions in cellular signals.

Preventive Measures

Shielded Areas: Create shielded areas where cell phone signals are not required, using Faraday cages or signalblocking paint. This prevents external signals from being jammed.

Secure Communication Channels: Use landlines or wired internet connections for critical communications that cannot be interrupted by signal jammer.

Legal Action: Report any suspected jamming activity to the relevant authorities, such as the FCC in the United States. Jamming devices are illegal, and authorities can investigate and take action against offenders.

Conclusion

Detecting a cell phone jammer involves observing sudden and consistent disruptions in cellular service, using signal detection tools, and employing professional equipment if necessary. If you suspect jamming, it's important to take appropriate measures to confirm and report the activity, as the use of jammers is illegal in many countries and poses significant risks to safety and communication.

Wi-Fi blockers and jammers are a notable topic in news reports about burglars in 2024, but is your smart home security in jeopardy?

Wi-Fi blocking sounds dangerous, but it's unlikely to be a threat to your home

One of the big selling points of smart home security is that it can make your home safer and more convenient. But you may have seen reports in 2024 about burglars using new technology to block Wi-Fi signals, jamming valuable camera systems or video doorbell connections and rendering them useless. This news report discusses police warnings about break-ins using Wi-Fi jammers in Los Angeles and Glendale, and here's a scary-sounding story about jammer burglars hitting homes in Minneapolis.

If you're worried, you're like many other homeowners who worry that their devices -- especially Wi-Fi cameras and sensors -- won't alert them in the presence of mobile Wi-Fi blockers, catch the thief, or even call a monitoring station for help.

Wi-Fi jammers do exist, but they are unlikely to pose a threat to your home or any of your devices.

Let’s summarize your reasons to stay calm:

The above reports are general messages from police to their communities, with little evidence of Wi-Fi jammers being used and only wealthy neighborhoods being robbed. In some cases, local reports explicitly state that police are only saying thieves “might” have used jammers, not that they’ve caught anyone in the act of committing robberies. Some burglar arrests, like this one in Connecticut in 2023, do provide evidence of jammer devices, but this is one of the very few that has been confirmed.

Smart home encryption helps prevent such attacks and can notify owners of problems immediately.

Burglars may not have the time or resources to buy and learn new technology. They’ll smash your windows or drill your door latches—blocking Wi-Fi isn’t their plan.

More likely, a suspected smart home security malfunction is the result of a dead wireless device battery or a failure of motion detection to activate due to a motion zone or detection sensitivity issue.

According to a 2019 FBI report, burglaries account for only 16% of property crimes, with only about 60% of those involving residential thefts and only about half of burglaries involving any kind of forced entry. It’s also worth noting that between 2010 and 2020, burglaries overall dropped by about 50%.

However, Wi-Fi jamming technology does exist, and despite FCC laws prohibiting the sale of such technology, thieves can still find and purchase jammers online.

NBC10 Investigators tracked down a cell phone sniffer who specifically targeted people using their cell phones on SEPTA bus routes. Not only did he admit to doing it, he thought it was a good thing.

The man, who calls himself Jonathan, told NBC10 Investigators, "I guess I'm taking the law personally, and frankly, I'm proud of it."

Jonathan said he doesn't want to hear people talking on their phones in public.

"It's still pretty annoying, and frankly, it's pretty rude," Jonathan said. Jonathan

said he was activating a cell phone jammer he bought online to block out conversations he doesn't want to hear.

"A lot of people are very loud and have no sense of privacy at all. When they feel like they're bothering me, I just screw in the antenna and turn the switch on," Jonathan said.

An NBC10 employee, whom NBC10 Investigators calls "Brooklyn," said she was horrified when she saw the man jamming passengers' cell phones while she was riding a SEPTA bus to work.

"He was clearly holding this device that looked like a walkie-talkie, with four thick antennas on it. I started watching him, and whenever someone started calling, he would press a button on the side of the device," Brooklyn said.

Brooklyn tipped off NBC10 Investigators, who went undercover and caught the phone thief with hidden cameras.

Minutes after boarding the No. 44 bus, NBC10 Investigators spotted Eric jamming a cell phone. Weeks later, they caught Eric as he got off the bus and told him cell phone jamming devices were illegal.

"From what I understand, it's more of a gray area. From what I understand, it's illegal to stop TV signals, radio signals. From what I understand, it's not illegal to jam cell phone signals under the FCC," Jonathan said.

But under federal law, it's illegal to use, possess, buy or sell a cell phone jammer. The federal government says violating the law could result in jail time and a fine of up to $16,000. Cell phone jammers are illegal for public safety reasons.

Dr. Rob D'Ovidio of Drexel University studies cell phone forensics and e-crime. D'Ovidio said some cell phone jammers can block GPS, two-way radios and even police radios if they are close enough.

"With a cell phone jammer, you can limit all types of communication tools that use radio frequencies. That has the potential to be a public safety disaster. It's a dangerous thing to cut off not only our government officials from communicating with the dispatch center, but also the public from communicating with 911," Dr. D'Ovidio said.

NBC10 Investigators asked Jonathan if he was worried about disturbing someone who was seeking emergency help.

"Certainly, if that happened on a bus, I think I would have been in that situation. Of course, I think that would have been a very different situation; I think I would have called 911 myself," Jonathan said.

SEPTA officials said they have received many complaints from 44 bus route passengers about lost phones. But SEPTA insisted that passengers are safe, adding that they have tested their system and handheld signal jammer alone are not enough.

SEPTA said all buses are equipped with panic buttons. Drivers can also alert police via digital destination signs on the front of buses. The transit authority said it has tested two-way radio communications and insisted cellphone jammers wouldn't affect it. But that didn't make Brooklyn feel any better.

Karyn Wall has lived in Lemon Grove for the past 20 years, and to her knowledge, her home has never been targeted by criminals. However, she recently learned how vulnerable her home is to would-be burglars.

“My husband and I feel very secure, but I know we may need to do something about the house, the interior, the lighting, etc.,” Wall said.

Shanah Clevenger is a crime prevention specialist with the San Diego County Sheriff’s Department who runs the free Lemon Grove Home Security Consultation Program. She’ll consider anything that can be done to bolster home security, no matter the budget.

“Some of my suggestions are quick and easy and don’t cost a lot,” Clevenger said. “I just suggest: do what you can, or do it incrementally until you feel your home is secure.”

That security measure includes protection against a relatively unknown type of wifi jammer. NBC 7 Responds spoke to cybersecurity expert Jim Stickley about these devices, who said that even though they are illegal in the U.S., there are several websites where you can buy them and have them delivered to your door.

"I mean, you shouldn't panic," Stickley said. "It's real, but the number of criminals who actually use it is relatively small."

How do Wi-Fi jammers work?

Jammers disable Wi-Fi devices by overloading the Wi-Fi frequency, or any radio frequency, and large jammers have a fairly wide range of interference, Stickley said.

"It could take out a whole house, or even a couple of houses around me, and take out all the Wi-Fi," Stickley said.

Once the Wi-Fi is down, criminals can break in without the cameras capturing it.

How to disable a WiFi jammer?

Wired cameras won't be affected by signal jammer, of course. Remember: The memory chip will record video whether or not there's Wi-Fi. Plus, some security systems offer systems that send owners notifications when Wi-Fi is down.

"If you get a notification that the Wi-Fi can't communicate with the camera, you can say, 'OK, something might be wrong,' and then you can call a neighbor and say, 'Hey, can you go check it out for me?'" Stickley said.

Wall said she couldn’t imagine coming home one day to find her home ransacked by strangers.

“That would be horrible,” Wall said. “That would be horrible because you’d be worried if there was someone else in the house and wouldn’t want to go in. That would be a very scary situation.”

Wall hopes to continue living safely in Lemon Grove for another 20 years.

The sheriff’s department said technology is important to keep your family and home safe, but it’s just as important that you and your neighbors look out for each other. They can also help start a neighborhood watch program.

The National Telecommunications and Information Administration (NTIA) has released a report detailing the results of its micro-jamming technology test conducted on January 17, 2018, at Cumberland Federal Correctional Institution in Maryland.

Test data showed that the micro-jamming signal interfered with commercial wireless signals inside the cells, meaning that if cell phones were used inside the cells, they would not work. However, at 20 feet and 100 feet outside the cells, the micro-jammer signal did not interfere with commercial wireless signals.

Department officers present during the January 17, 2018 test reported that while their cell phone signals were blocked inside the cells, their phones still worked when they stood a few feet from the cell windows.

"These encouraging test results mark a step forward in our efforts to combat the security threat posed by contraband cell phones," said Beth Williams, Assistant Attorney General for the Justice Department's Office of Legal Policy. "The results show that this micro-jamming technology has the potential to have a localized impact. This is an encouraging sign that we are closer to solutions that make our communities safer and help prevent the continuation of criminal activity within prisons."

The data in the report will be used by the BOP and the Department to understand the effectiveness of micro-jamming, further evaluate jamming technology, and develop strategic planning recommendations.

Contraband cell phones continue to be a correctional security and public safety concern for the Bureau of Prisons and state and local correctional institutions. Across the country, inmates use contraband cell phones to direct gang activity, operate criminal enterprises, distribute child pornography, intimidate witnesses, and facilitate the commission of violent crimes. "This test is just one part of our ongoing efforts to disrupt and disable dangerous contraband cell phones in federal and state prisons," said Assistant Attorney General Williams.

The Bureau of Prisons will continue to evaluate cell phone detection and blocking technologies and work with federal partners and Congress to find cost-effective options to combat this threat to prisons and public safety. The agency does not endorse any specific vendor or product.

Carr Pushes for Federal Legislation to Combat Contraband Cell Phones in Prisons

ATLANTA, Ga. – Attorney General Chris Carr and 21 other attorneys general are urging congressional leaders to pass legislation that would allow states to implement cell phone jammer systems in correctional institutions. Currently, federal law prohibits the use of jamming technology, including jamming cell phones. Meanwhile, prisons across the country are using contraband cell phones with no way to stop them.

“Cell phones in the hands of criminals are an ongoing safety concern, not only for Georgia, but for correctional institutions across the country,” said GDC Commissioner Tyrone Oliver. “We appreciate Attorney General Carr’s support in finding a solution to this problem, which is critical to our commitment to public safety.”

As of January 1, 2023, the GDC has conducted 126 full facility searches and seized more than 23,000 contraband items. Last year alone, 8,074 contraband cell phones were seized.

In a letter sent on January 25, 2023, the Attorney General outlined the national challenges associated with contraband cell phones.

The letter reads: “The use of contraband cell phones by inmates is one of the most serious issues facing prison administrators today. Inmates use contraband cell phones to organize murders, riots, drug trafficking, fraud, etc. By using contraband cell phones, inmates can easily continue their criminal activities inside prison.”

Previously, Congress has introduced several bills to address this issue, including H.R. 1954 in the 116th Congress and H.R. 864 and S. 4699 in the 117th Congress. However, these bills have not made any progress and have never received a vote.

To jam a 5G signal, an intelligent adversary can detect unencrypted synchronization signals to obtain the physical cell identity (PCI) and then launch a targeted cell phone jamming attack on the physical broadcast channel (PBCH). This intelligent jamming (PBCH-IJ) disrupts the master information block (MIB) decoding, leading to denial of services for users trying to access the PCI cell. The proposed method in the paper suggests detecting PBCH-IJ by analyzing the principal direction of PBCH demodulation reference signal space at the user side, as this direction is significantly impacted by PBCH-IJ under low mobility scenarios.

Jamming attacks on 5G signals can be executed by exploiting various vulnerabilities inherent in the 5G network architecture. One common method involves targeting the synchronization signal blocks (SSBs) during the initial access phase, as these blocks are unencrypted. An intelligent adversary can detect these signals to obtain the full physical cell identity (PCI) by sniffing, and then use the PCI to attack the physical broadcast channel (PBCH) extraction through targeted jamming. This type of PBCH intelligent jamming (PBCH-IJ) disrupts the decoding of the master information block (MIB), leading to severe denial of service for users attempting to access the PCI cell. Another approach involves using a multi-antenna jammer to interfere with the downlink signals from femto base stations (FBS) to femto users (FUs) in a two-tier 5G heterogeneous network (HetNet). This can be particularly effective in dynamic environments where traditional anti-jamming techniques like frequency hopping (FH) and direct sequence spread spectrum (DSSS) lack self-adaptive capabilities. To counteract such jamming, advanced techniques like federated deep reinforcement learning (DRL) have been proposed, which optimize beamforming and power allocation to improve the achievable rate at FUs despite the presence of signal jammer. Additionally, jamming detection in 5G can be enhanced by using the "EVM-vs-RB" measurement, which calculates the Error Vector Magnitude (EVM) for each Resource Block (RB). This method is more sensitive and informative, capable of detecting jamming even at high Signal-to-Jamming Ratio (SJR) values, which traditional metrics fail to identify. These methods highlight the sophisticated techniques adversaries can use to jam 5G signals and the equally advanced countermeasures required to mitigate such attacks.

I was there in an exhibition yesterday. Most of the times, i was not able to use my cellphone data internet. But, i was able to make calls with the phone most of the times. Now, i have a doubt here. I happened to call a friend who was also to the same show, and he did say that he was not able to access the cellphone internet there. He said that they had used Network Jammers, though he was not certain about it.

My question here are:

1) Can network jammers only restrict data and not calls? How is it possible??

2) Will there be separate jammers for 2G/3G/4G/5G, based on it's spectrum?

3) Are jammers free of health hazards?

4) What could be better designs to use than jammers?

network jammers can selectively block data services while allowing voice services. This is possible because voice and data services use different network protocols and frequencies. A network jammer can be designed to block specific frequencies and protocols while allowing others to pass through.

there are different types of cell phone signal jammer for 2G/3G/4G/5G networks since they operate on different frequencies. Each technology operates in a different frequency band and therefore requires a specific jamming device.

Network jammers emit high levels of electromagnetic radiation that can be harmful to humans if they are exposed to it for extended periods of time. The radiation emitted by a jammer can cause cancer, DNA damage, and other health problems. Therefore, network jammers are not free of health hazards.

There are alternative methods to restrict network access in specific areas without using network jammers. For example, using Faraday cages can block all electromagnetic signals from entering or leaving an enclosed space. (There is graphite paint for example for walls, normally it is connected to ground with metal strips under the paint.) Another approach is to use signal blockers that selectively block specific signals without affecting other services. However, the effectiveness of these alternatives is limited, or they would just be too expensive, and jammers remain the most effective way to block specific network services in a specific area.

The possible misuse of internet can be one reason to block data services. Also, the method were used, i'm not sure now, when a person decorating high post in the country uses public transport infrastructure.

The possible reason would be high capacity which the BTS (for that particular cell) wouldn't be able to provide. This point needs to be valid, since the network used to fall back to lower generation at times. Again, i'm not sure how the BTS would automatically cut off the channel width based on the number of connections.

As said above, in order to prioritize the audio calls, the frequencies used will get the connectivity to 2G or 3G.

NBC News reports that online retailers and drone technology companies are marketing RF jammers as drone deterrents or privacy tools, thereby circumventing laws that prohibit the sale of such devices in the United States.

The warning issued by the Federal Communications Commission (FCC) states that signal jamming devices can block emergency calls and pose a serious risk to public safety communications, while also interfering with other forms of everyday communications and air navigation systems.

The FCC said: "It is a violation of federal law to use phone blocker, GPS blockers, or other signal jamming devices designed to intentionally block, disrupt, or interfere with authorized radio communications. Use in businesses, classrooms, residences, or vehicles is not exempt. Local law enforcement agencies do not have independent authority to use jamming devices; federal law enforcement agencies may use them under applicable regulations under certain limited exceptions."

The FCC warning also states that "it is illegal to advertise, sell, distribute, import, or otherwise market jamming devices to consumers in the United States"

But NBC reports that Amazon third-party sellers, independent online stores based in China, and small domestic companies that specialize in drone-related equipment are all ignoring the law. The FCC told NBC that it is investigating the sale of jammers, including on Amazon.

As part of its investigation, NBC spoke with the CEO of a U.S. company that offers portable anti-drone radio frequency jamming devices online. The CEO told NBC that the devices are easily available if consumers have the money, but they mainly see interest from large companies and government agencies as they prepare for domestic drone terrorism.

There are more people selling "jammers." The devices can block cell phone calls, text messages, Wi-Fi networks and GPS systems and can be used to cause chaos in public places.

The small, battery-powered devices can be used to create "blind spots" in a small area (usually around 30 feet) and have been used by movie theaters, restaurants and schools to prevent people from using their phones. But they can also cut off 911 calls, interfere with navigation near airports, and have been used to disrupt radio communications near police stations. FCC officials said they have noticed an increase in the flow of jammers, which are banned by federal law, into the United States. Many of the cheaper versions, which sell for as little as $25, are imported from Asia, according to the agency.

It is illegal to sell, advertise, use or import jammers under the Communications Act of 1934, which prohibits blocking radio communications in public

The FCC said cities including Orlando, Philadelphia, Austin, Mississippi, Charlotte, North Carolina, Washington, D.C., Cincinnati and Corpus Christi, Texas, advertised jammers on the site. Officials said they do not believe the cases are related.

"Simply posting an ad for a signal jammer on a site like Craigslist.org is a violation of federal law. Signal jammers are contraband for a reason," Michele Ellison, director of the FCC's enforcement bureau, said in a statement. "One person's moment of peace or privacy could very well jeopardize the safety and well-being of others."

Most sellers advertised jammers as a way to take an "undisturbed nap" on a bus, quiet a classroom or keep your area "free of interference," without mentioning the more nefarious uses the device could be used for, according to the citations.

"We are increasingly concerned that individual consumers operating jammers do not appear to understand the serious consequences of using jammers," one citation reads. "Instead, these operators mistakenly believe that their illegal operations are personal convenience or should be excused."

Keith Grabowski allegedly advertised on Philadelphia Craigslist for a "cell phone jammer, WiFi signal jammer" for $300. He stated in the ad that "due to the nature of this item, we are disclosing very few details," that the jammer was "not a toy," and that "I just want to get rid of it as quickly as possible."