In life, we have more "radio", US / China has such a group of secret agent. . .
A few days ago, a US satellite was engaged in the "scrap" of Tianjin parking lot. The incident of "scrap" has caused everyone's interest. The essence of things is actually because this satellite chooses a narrowband radio band of cold doors, that is, 1400-1427MHz, this The frequency band is also a control band in my country.
Normal in situations where no interference, this satellite can obtain more accurate earth soil water information. But unfortunately, the wireless transmission used by video surveillance equipment in a parking lot in Tianjin has a fault, resulting in frequency offset! Biased this band!
Generally speaking, everyone is talking about public morality, and various countries are strictly observing international regulations. For example, after my country's information from the US NASA, I actively investigate the suspect. The power of these devices is very low. It is not possible to directly burn wireless devices from satellites far in space, and only because of wireless interference, there is no scrap satellite.
Under normal circumstances, once the frequency band is sold, the FCC prohibits anyone else from using the particular frequency band.
But there are always rogue equipment to be in this frequency band, such as baby monitors, cordless phones, and mobile phone repeaters are the most common illegible equipment. The interference generated by these devices will deteriorate the overall performance of the network.
In daily life, for example, 2.4GHz cordless phones will also affect the performance of barcode scanners and inventory tracking equipment in retail environments. There is also the "pseudo-base station" that has been hit by the public security organ, which is more illegally utilizing RF signals to send fraudulent SMS, spam messages.
Foreign industry with "radio hunters"
The popularity of personal electronics means that the potential of RF interference is getting bigger and bigger. But because operators buy new spectrums are very difficult and expensive, they will continue to vigorously defend their licenses they hold.
This "RF Hunter" industry is reported on the IEEE Spectrum.
Kevin Argentieri is a Radio Hunter. He tracks devices that cause radio frequency interference every day, and then try to convince the owner to close it. Generally, he uses a portable spectrum analyzer to find the source.
Most of the time, he can find the source one day. This is a subtle process, involving the door of the stranger, search for the illegal equipment in their house, politely reminds the owners, if such equipment, they may be fined $ 16,000 a day.
Argentieri works for P3, which is searching for RF interference with national operators including Verizon, AT & T, T-Mobile and Sprint. US operators pay huge amounts of funds to the US Federal Communications Commission to obtain exclusive licenses for radio spectrum.
The above picture is that Argentieri is tracked from the customer's roof base station to the construction site opposite the street. He found that there were employees with cable TV antennas. This interference appears in the 700 MHz band, which is popular in cable TV companies and wireless operators.
Cable TV companies are allowed to use 700 MHz, as long as their television signals are still controlled in a cable connected to the customer TV. But if these cables are divided into two sections, or they are smashed by squirrels (this is really happening), the cable will projection to the air.
These "leak" television signals interfere with the cellular signals of other customers of 700 MHz. The honeycomb signal can even go directly to the disconnected cable, distort the TV program. His next step will be to notify cable TV providers in the region's suspicious leaks and ask them to repair.
China has "electric wave guard"
The pseudo base station is mentioned earlier, and now, the general pseudo-base station has range from two or three hundred meters to 3 kilometers.
"Pseudo-base station" is usually hidden in the city center, the population intensive area, small size, strong liquidity, and is very concealed.
China has a profession is "electric wave guard", they will capture signals in the area of user complaints, carry out uninterrupted monitoring, gradually narrow the range, and finally lock the launch source.
Is there a bit like a device that found with foreign radio hunting hands? Both of the two have a directional antenna, both portable. The field power value of the signal identifies which signal may be illegal, followed by changes in this signal strength to determine which direction of the signal comes from.
Original link: https://www.eeboard.com/news/wuxian-8/
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