In January 2007, NHK Hall installed mobile phone jammers to ensure that audiences are not disturbed by mobile phones when watching performances. The device blocks mobile phone signals by emitting radio waves of the same frequency as base stations, thus creating an interference-free environment with "over-range coverage".
Working principle of mobile phone jammer devices
Mobile phone jammers prevent mobile phones from communicating with base stations by emitting radio waves stronger than base stations. Mobile phones will mistakenly think that they are out of the signal coverage range and cannot receive and send signals normally. This technology cleverly "impersonates" base stations, sends empty messages, and prevents mobile phones from connecting. The coverage range of this device can reach 100 meters in diameter, which can effectively block mobile phone signals in a large area.
Application and effect
Similar mobile phone jammers have also been installed in NHK Hall and other large theaters such as the Imperial Theater, the National Theater, and the Tokyo Takarazuka Theater. These devices are usually installed in inconspicuous locations, such as next to the speakers on both sides of the stage, to ensure that the audience will not notice their presence. At NHK Hall, these devices blend in with the color of the speakers and are not easy to detect.
Legal and technical considerations
In Japan, the use of mobile phone jammers requires permission from the Ministry of Internal Affairs and Communications. Although these devices have stronger radio waves than base stations, they are in compliance with the provisions of the Radio Law because of their smaller and more precise coverage. NHK Hall finally decided to install them after multiple tests to ensure that the jammers would not interfere with the normal use of equipment such as wireless microphones.
Necessity of mobile phone signal jammers
In recent years, the number of mobile phone users has increased significantly, and the phenomenon of using mobile phones in inappropriate occasions has become more and more common. Although cinemas and theaters constantly remind audiences to turn off their mobile phones before performances, some audiences still forget or ignore these reminders. For this reason, installing mobile phone jammers has become an effective means to ensure a distraction-free viewing experience.
The popularity of mobile phone jammers reflects the increasing dependence on mobile phones in modern society, and also highlights the importance of public etiquette and viewing environment. These devices not only effectively block mobile phone signals in technology, but also have been widely recognized in practical applications, providing audiences with a quieter and more comfortable viewing environment.