A wifi jammer is an electronic device that prevents signal transmission between WiFi networks. By using the same frequency as a cell phone, WiFi jammers can strongly interfere with communication between callers and receivers. It effectively blocks signal transmission from networks such as 4G, 3G, GSM and WiFi Bluetooth.
Cell phones operate on different frequency bands in different countries. For Canada, the 1900 MHz band is the main frequency band, especially for urban areas. 850 MHz is used as a backup in rural areas. The United States uses the 850 and 1900 MHz bands depending on the region. Europeans tend to use the GSM 900 and 1800 bands as standard bands. The Middle East, Africa, Asia and Oceania also use these frequency bands. In Russia and some other countries, local operators have been licensed for 450 MHz to provide CDMA coverage. Therefore, the frequency band pages blocked by signal jammers in different countries are different.
Considering that WiFi signal blocking devices are quite complex devices, there are not many simple ways to make effective and cheap portable cell phone jammers. Their creation is usually in the hands of complex machines, rather than error-prone people. Radio jammers are actually illegal in the United States, so it can be difficult to reach them if you don't have the right resources. Using a cell phone while driving in Florida was completely legal. Jason R. Humphreys used a cell phone jammer produced for about two years, until the FCC and the sheriff's agent finally caught him.