The use of jammers is a problem because they block license-free frequencies that are not part of the jammer, and it is illegal to interfere with license-free frequencies. cell phone jammer can block signals in the range of tens to hundreds of feet. The FCC is most concerned about buying jammers that will prevent emergency personnel from communicating with callers.
Americans usually buy jammers online. The US Federal Communications Commission (FCC) tries to prevent other countries from selling jammers to the United States and sending them to the United States, but some jammers slip away from the mail. The United Kingdom, Canada, Switzerland and Australia also do not allow the use of cell phone jammers.
However, putting it on the Internet (200-300 Euros) does not seem complicated. Cell phone signal jammers are the emission of information clouds that prevent elements from communicating with each other. The message is sent by the sensor but cannot be heard from the central console. Imagine, like two people chatting in a bar, a football team singing to celebrate their victory. The two men will always face each other, but they will no longer get along.