Your phone relies on radio waves to transmit data and sound to the cell tower. When the phone works, the radio waves run on a specific frequency range, with a baud rate and modulation method.
The typical cell phone jammer on the market support the following frequencies:
The operating frequency bands are CDMA800, GSM900, DCS1800, and PCS1900. It can control the range of about 40 meters in diameter, using DC-DC converter input voltage and 5V output voltage.
After listing 3G signals, the operating frequency bands of signal jammer on the market today have also been upgraded from the previous four frequency bands to five. Based on the previous four frequency bands, the frequency band of 2100 to 2200 has been added. It is used for blocking and interfering with the 3G band.
Today, telecommunication technology is fast-growing. As a unique talent in the communication family, mobile communication plays a vital role in our daily life, business, industrial, agricultural, and almost every corner of our society. It makes our life easier. However, some problems have appeared that cannot be ignored.
The mobile phone has brought people trouble and even caused security risks. It becomes a new unsafe factor, which brings hidden dangers to the safety production of business; It becomes a new crime method and affects social stability, so we should be able to destroy it artificially in some places or limit this kind of network to avoid the harm caused by the mobile network, so the cell phone signal jammer arrive.
The cell phone jammer, in essence, implements electromagnetic interference on the wireless network on which mobile phone communication depends so that the mobile phone cannot be connected to the Internet and thus cannot transmit information to the cell tower.
The cell phone jammer scans from the low-end frequency of the forward channel to the high-end frequency at a certain speed during the working process. The scanning speed can cause garbled interference in the message signal received by the mobile phone. The mobile phone cannot detect the data sent from the base station, so the connection cannot be established.
It consists of a Mobile Switching Center (MSC) and each Base Station (BS) under its control. Each base station includes a receiver and a transmitter. Although the radio signal transmitted by the base station covers a circle on the ground, considering the coverage of the entire network’s Effectiveness and connection, the actual scope of each base station is a regular hexagon centred on the base station, also called a cell. The total range covered by all base stations is equivalent to the overall arrangement of adjacent regular hexagons.
Therefore, mobile communication is also called Cellular Communication. As far as the mobile phone in each cell is concerned, it communicates with the base station through the uplink frequency of the channel and then transfers the signal to the MSC to communicate with other phones. The radio frequencies received by the mobile phone are divided by frequency band:
- GSM 925-960MHz,
- DCS 1805-1880MHz,
- CDMA 869-894MHz,
- PHS 1900- 1990MHz,
- SCDMA 450- 470MHz,
- TD-SCDMA2010- 2025MHz.
Each frequency band is divided into many channels with a specific bandwidth. Each cell uses several channels, one of which is called the Broadcast Control Channel (BCH), and the other is called the Traffic Channel (TC). In the standby state, the mobile phone starts the receiving circuit intermittently to receive the BCH in the cell where it is located. According to the field strength of the BCH signal, the signal bar is used to display the signal strength indicator. When making an outgoing call, the first step is to ask the MSC for instructions through the BCH, and the MSC handles the calling or the called party. The MSC assigns a service channel to the mobile phone according to the channel status in the cell so that the mobile phone jumps from the BCH to the service channel, and then the call between the two parties is established.
As you can see, the BCH in the network is the precondition for telecommunication. If your phone cannot find the BCH, there will be no network, and the signal bar on your phone is always at zero, so you cannot make or receive calls. That’s what would happen when you turn on the cell phone jammer.
Since there are many channels in any frequency band of mobile communication, each channel can be used as BCH. The MSC is the decision maker on which channel will be used as BCH. Generally, the frequencies between channels in the same cell should be pretty different to prevent crosstalk between channels with similar frequencies. For example, after using channel 5, do not use channels such as 4 and 6. The same channel and adjacent channels cannot be used within a cell. Among the several channels allocated in each cell, one of the channels is designated as BCH, and the rest are traffic channels.
Due to BCH’s non-fixation, the use of signal jammer is very versatile. In addition, there may be more than two BCHs under the network in the adjacent area of the cell. Therefore, it should be correct when using the signal jammer.
The other concept worth mentioning about signal blocking is the signal strength of your jammer must be higher than the wireless network. That’s very important to ensure the jamming signal can override the cell phone signal. Generally, the closer to the base station, the stronger the field strength of the local BCH. That also explains why you can’t get a good result if your location is too close to the base station.