About the Gain of GPS Antenna
How many dB is the best gain for the GPS antenna? Many people think that the greater the gain, the better the signal. This understanding is wrong. The gain of the antenna is directly related to the GPS positioning module. In the early GPS module, the maximum gain set at the earliest is 35dB, and the minimum is 17 dB. Therefore, the input gain strength at the module end is between 17-35dB. If it is too small, the signal will be very weak, and the receiving speed will be slow. It may not be able to locate. If the signal exceeds 35dB, and the signal is too strong, it will cause the module to hit itself, resulting in signal loss.
Therefore, the gain of the external GPS is usually 28 dB. For the normal RG174 line, the attenuation of the GPS signal is about 1.3dB per meter. If the line is 3 meters long, the loss is 3.9 dB, 28-3.9 = 24.1 dB, so there is still 24.1 dB at the input end of the module, which is qualified.
The GPS antenna placed inside the device normally has a gain of 19dB, because the built-in cable of the device is relatively short, usually between 50mm or 150mm, so 19dB is completely enough.
