In recent years, signal jammer have been widely used to completely eliminate these phenomena from the precedent that communication equipment has been used for fraudulent activities in university entrance examinations.
So what is the principle of mobile jammers used in college entrance exams? In fact, this is the time it takes a mobile phone to send and receive messages. Cell phone jammer are like loud devices. The output of the "noise signal" is too loud to hear the original sound. , Also known as wireless jammer. In short, the role of the shield device is not to block the phone signal, but to obstruct or cover it. It supports the use of electromagnetic signals and is very convenient when processing a large number of harmful signals.
Phones are always used when using wireless communication equipment, but there are also invisible wires that act as mobile phone base stations. The first step in making and answering calls is to connect to a nearby mobile phone base station. When a left-handed person calls a right-handed person with a mobile phone in the left and right hands, the electromagnetic waves from the mobile phone are not transmitted directly from the left hand to the right hand, but in a simple case, the distance from the mobile phone to the left-handed road. Is 100 meters.+
Therefore, the signal in the examination room is disturbed. This caused annoyance to mobile phone users in the examination room and reduced call quality. Please support the flowers of your homeland for a few days.
But is this mask really effective? The entire frequency range of electromagnetic waves is very wide, from the lowest Hz to the largest hundreds of GHz. Any segment can be used as a communication signal, but some common protective equipment has "sufficient skill" and the "five types" of "incomplete sound" shields block only a few tools. There are things you can't do. Unshielded tape communication frequency Tape communication can be used.
Therefore, it is necessary to increase the number of 3G / 4G phone jammers and continue to cover all areas.