Recently Miss Yi will put her cell phone on the windowsill the moment she comes home after work. Her new strange habit is all about to make sure her cell phone can operate normally. Several days ago Miss Yi’s cell phone cannot work as normal even though the signal bar is full. The other residents of the building also find that their cell phones have trouble to use. They cannot call someone and receive someone’s call. According to the investigation, there is no mobile phone signal jammer around the building. Many residents have to move out of the building because the terrible cell phone signals.

         After a comprehensive investigation, they find the reason. It is because some residents set up mobile signal enlarger without permission. The enlarger sends radiation to extend the scope of the owner’s cell phone signal, but it jams other person’s cell phone signal at the same time. It acts like a mobile phone jammer.