How does jamming work

Jammer (jammer)

Since January 1, 2018, the import and possession of a jammer has been strictly prohibited in Switzerland and in several countries of the European Union. The regulations for these devices, which are also called "blockers" or "jammers", have thus been tightened, because previously the ban only applied to their placing on the market and use. Jammers can be dangerous as they prevent all cellular traffic and make emergency calls impossible. Most of the time, the advertisements for this type of device are deceptive: they give the impression that their use is legal and fail to make it clear that even possession is illegal.

The previously expensive and bulky jammers, which were limited to neutralizing mobile phone traffic in the GSM 900 MHz frequency band, have followed technological developments. They have become smaller and cheaper and can now disrupt a large part of the spectrum. With some models, not only the mobile phone bands (GSM, UMTS, LTE, ...), but also positioning systems (GPS, Glonass, Galileo, ...), data transmission networks (WLAN, RLAN, WiMax, ...) or wireless alarm systems be disturbed. Usage has also evolved. While the devices were previously only used to prevent cell phone calls in trains, restaurants or cinemas, today they are also used for criminal activities: theft of cars or trucks that are transporting valuable goods (by deactivating the location of the vehicle), theft in houses and homes (by neutralizing the cordless alarm system) etc.

Due to the spread of jammers, a tightening of the law became necessary: ​​With the entry into force of an amendment to the Telecommunications Act (FMG) on January 1, 2018, the import and possession of jammers was banned. The manufacture, offering, making available on the market, commissioning, construction and operation of these devices also remain punishable.

By banning this type of facility on its territory, Switzerland is following the EU member states and other countries such as B. the United States.

A threat to security

The use of jammers is strictly forbidden because it not only causes inconvenience for users of the radio frequency spectrum and encourages criminal activities, but can also have serious consequences for security. In this way, emergency calls can be blocked in the event of an accident or the alerting of emergency services such as the fire brigade, police or ambulance. This can also lead to serious problems in civil aviation, which is increasingly using the global navigation satellite system (GNSS) to improve navigation performance and the monitoring activities of air traffic control.

In the FMG, the use of jammers is tantamount to deliberately disrupting the radio frequency spectrum, which can be punished with a fine of up to CHF 100,000. OFCOM intervenes systematically in such cases

Jammer for authorities

It looks different in prisons. Detainees use their cell phones to organize criminal activity or plan an outbreak. Another example is the defusing of explosive objects that can be detonated by radio. The FMG expressly provides for the possibility for prisons and police authorities to use jamming systems to prevent cell phone calls in their vicinity. The operation of such a system must be approved in advance by OFCOM.