FC20_N integrated application problem

We have a project. When the WIFI module FC20_N is integrated with the GPS, after the actual test WIFI function is turned on, the GPS performance will decrease, and the C/N value will drop by more than 5dB. We tried to short the WIFI antenna feed point directly to the ground, the power supply tried to independently power supply and other methods, and found that the WiFi function only turned on, the GPS performance dropped a lot. Please the Quectel engineer to give some advice and analysis.

thanks a lot,

Hi Jack,
thanks for your question. which country are you from? we can arrange related FAE engineer to support you directly. do you use embeded GPS function of EC25? generally wifi module don’t have influence on GPS module ,because they working frequency is different, could you send your schematic&pcb layout files to us for riview, could you turn off WIFI function when you use GPS funciton as a walkaround way, but root casue should be found.

Hi, Peter,
thank you for your reply, I am in Shenzhen, Guangdong. At present, this case is for foreign customers. The EC25 is equipped with FC20_N, but the GPS is not embeded GPS function of EC25. Instead, it is built with other GPS chips. The actual application of GPS function and WIFI function will also be used together. We have encountered this problem for some time. We have not found the root cause of the problem. We want to solve the problem as soon as possible and never leave the problem to the customer. I look forward to your FAE engineers helping us analyze and solve problems together. We can provide relevant schematics and PCB files to analyze the problem.

thanks a lot,

Jack, we had the exact same problem and measured noise from the FC20 in the GPS band. The only way we got it resolved (better) was to move the GPS antenna further away from the FC20.

Hello, thank you for your instructions. Are you testing the radiated noise of FC20? Is it noise from the antenna end or the power supply or the ground noise of the board? The original factory of this module should have been tested for certification. At present, the Quectel FAE gave us advice on the reasons for power stability. We are still trying to analyze and have not found the root cause. Our products are relatively small, the GPS antenna is built in, but in fact there are other boards between the GPS board and the WiFI board.

Sorry for the late response. I think they passed the emissions tests as the noise is low but enough to interfere with our GPS. The noise seemed to come from the module, not the ground, power supply or antenna. Our board was reviewed by quectel with no findings against it. Our GPS antenna was approx. 5mm away from the wifi module. It was now moved about 12mm away. We can still see interference but it is a lot better now.