Hi,
We have a custom nRF9160 board with chip antennas for LTE and GNSS. They are Ignion antennas with matching circuits customised to our board dimensions. We also use a SKY65943-11 LNA for the GNSS.
The LTE-M works really well, however, we have had multiple tries to get the GNSS working with no success. Some things we have checked/fixed.
- Our first issue was with the LNA not even activating since we have a custom board and "AT\%XCOEX0=1,1,1565,1586" wasn't included. We since have included it and now the COEX0 pin goes high.
- We compare against an nRF91 Thingy and its GNSS chip antenna - which gets a fix whilst our board can't.
- It sometimes jumps between tracking 0 and 1 satellites but always goes back to 0. Only a few times has it jumped to two satellites for a short fix.
- We weren't sure if we should have any filtering between the nRF91 and the LNA, since we don't have an external antenna.
- I've included the relevant schematic and layout of the GNSS module.
Is there anything I am missing, is wrong with the schematic, or that I need to do for a custom board? Please let me know if you need more data.
Cheers,
Callum
