Although the time of the college entrance examination has indeed been delayed due to the epidemic recently, in order to ensure the safety of the details of the examination room, the corresponding measures have not been reduced at all. Operators have actually released news one after another. During the exam period, according to the needs of the Education Bureau, the cordless signal jammer will definitely be turned on, which will inevitably affect the interaction quality of mobile phone users in the whole school. Communications will not return to normal until the test is complete. What are the characteristics of opening the signal jammer throughout the college entrance examination? Proctors at the entrance to the test room brandish metal detectors. Does it really work?
But in general, the regular frequency bands of electromagnetic waves used by the three major operators are distributed in the 850-4900MHz range. If the organizer of the college entrance examination wants to block the mobile phone signal in the examination room, it is impossible for the 2G/3G/4G/5G base stations near the examination room to not work, otherwise all communication devices in this area will usually not be able to connect. This is the only way to block cell phone signals in the testing area.
When it comes to shielding smartphone signals, the first thing everyone thinks of is metal reinforcement, that is, placing the phone in a closed steel box, and using steel to block the spread of electromagnetic waves. Nonetheless, it is clearly unwise to set all levels of the assessment area to metal-enclosed levels. So what should we do? It's very simple, just need a small mobile phone signal jammer to block all smartphone signals in the examination room.
The smart phone signal jammer checks the radio frequency band of the forward channel (the network from the base station to the mobile phone) to the high frequency band at a certain speed during the whole working process, and causes interference in the process of obtaining the message through the smart phone signal to ensure that the smart phone cannot A signal from a base station is found. Typical data transmission makes it impossible to establish a link with the base station, and there is also a state of no signal and no solution. For example, when the phone interacts with the base station, the signal jammer acts like an abettor, intentionally making sounds around you. The sound signal is so loud that the phone can't hear what the base station is saying, and the base station can't hear what the phone is saying. In fact, this is not to protect the signal of the mobile phone, but to hide the signal sent by the smartphone in a large number of noise signals to achieve the effect of anti-interference.
The mobile phone signal jammers currently used in the evaluation area are all conventional frequency bands, which can block all frequency bands of the operator's 2G/3G/4G/5G, and can also block all wi-fi signals and Bluetooth signals. The above is the concept of mobile phone signal jammer. However, the frequency band of electromagnetic waves ranges from a few Hz to tens of hundreds of GHz, and each segment can interact as a signal. Will the evaluation room use some special regular frequency bands? This applies to various other radio communication tools, and in this case radio interactive devices that "come into being" with fixed regular frequency bands. The operating frequency bands of these devices are selected outside the frequency range covered by mobile phone jammers, and mobile phone jammers will not work on them.
For this special radio communication equipment, the assessment room is specially equipped with a monitoring vehicle equipped with a radio monitor for real-time monitoring of radio wave signals of unknown origin. So how precisely can a radio detector function? Because the electromagnetic wave has the characteristics of "near large, far small", by constantly moving the detection vehicle, the tracking tool can find the position of the signal transmitter according to the distance and the strength of the signal, and capture the offenders who use these radio interaction tools on the spot. Today, drones have really appeared in the college entrance examination area, which can deliver signals faster. So neither smartphones nor these unique radio tools can contribute in the realm of college admissions assessment.