With Nordic Thingy:91™ v1.4.0, the connector type changed to a Hirose U.FL compatible connector (I-PEX MHF).
An external active Global Positioning System (GPS) antenna can be connected to connector J2.
Figure 1. External GPS antenna connector on Nordic Thingy:91 v1.4.0
When an external antenna is used, the on-board Low-Noise Amplifier (LNA) should be disabled. The LNA enable signal is controlled by the COEX0 pin of the nRF9160, and its function is set by the AT%XCOEX0 AT command. The LNA makes the GPS receiver more sensitive to GPS signals and less sensitive to interference from other sources nearby.
Figure 2. GPS circuit schematic for Nordic Thingy:91 v1.4.0
To disable the on-board LNA, the following needs to be done in the firmware:
- In the file nrf/boards/arm/thingy91_nrf9160/board_nonsecure.c, change
the line
#define AT_CMD_COEX0 "AT%XCOEX0=1,1,1570,1580"to#define AT_CMD_COEX0 "AT%XCOEX0". - Save the file, and rebuild the firmware as described in Working with Thingy:91 nRF Connect Software Development Kit (SDK) documentation.