Satellite signal interference and anti-interference

Microwave interference

Microwave interference is the biggest killer of satellite reception, and it usually occurs most frequently in the C frequency band, but also in the Ku frequency band, but it is very rare. Microwave interference can be divided into fixed frequency interference and radar full frequency interference.

Fixed frequency interference

When the satellite antenna has not been aligned, for example, many signals that are not transmitted by the satellite are found from the spectrum analyzer, and these signals will have a specific frequency regardless of the direction of the antenna. This situation is called fixed frequency interference.
These interference sources usually come from the illegal transmission of SNG microwave signals by the microwave transmission stations of the telecommunications bureau, the military, radio and television stations, and cable television stations. The field strength of the general interference signal can range from C / N 0 to 40 dB. If the frequency of the satellite signal overlaps with the frequency of the interference signal, the satellite programs within the frequency of the satellite signal that are overlapped cannot be received.

Radar full-range interference

"Radar full-frequency interference" as the name implies is that the entire satellite band is interfered by radar. This interference is difficult to detect from the spectrum analyzer during the antenna installation process. However, if the SPAN of the spectrum is increased a bit, you can find every In the period of 6 ~ 12 seconds, the signal of the entire satellite band will be 1 ~ 3 dB higher than C / N instantaneously, and then restore the original waveform. This phenomenon is called radar full-frequency interference. These interference sources usually come from airport radars and military radars. This interference usually affects the reception of satellites by digital signals more than analog signals.
If the analog signal is swept by the radar wave, many obscure white spots appear on the program screen, and it is not easy to detect if you do not pay attention to it. If the digital signal is swept by the radar wave, the screen will stop completely for 2 ~ 3 seconds, and this phenomenon will continue.

Anti-microwave interference

If there is microwave interference in the place where the antenna is erected, the anti-interference methods are: 1. Looking for shielding 2. Erecting anti-interference net 3. Install anti-interference device.
1. Looking for shielding: it is looking for the dead angle of the radiated interference wave. Both the interference wave and the satellite wave travel in a straight line and will be reflected. The difference between the two types of radio waves is that the field of the interference wave is tens of millions of times stronger than the satellite wave, and the satellite wave is not reflected by the antenna The surface absorbs, and the interference wave will reflect around obstacles and buildings
2. Erecting anti-interference net: It is to set up wire mesh around the antenna to prevent the entry of interference waves. When erecting an iron grid, the height must exceed LNB and cannot block the direction of travel of the satellite signal.
3. Anti-microwave jammer: a microwave filter installed before the signal enters the LNB

The above anti-jamming methods can only target weak microwave interference. If medium or strong microwave interference is encountered, the antenna can only be moved to a place without interference. There is no other way.

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