Enabling external GNSS antenna on the SOM

Edge Systems
1

Hi, I'm trying to use an external GNSS antenna with the Tracker SOM.
However, i can't seem to find a way to e.g. control the GNSS_LNA_EN pin.. I have found a setAntanna method inside ubloxGPS.cpp which seems t accept a "UBX_EXTERNAL_ANT" (0x01) value but it doesn't seem to have any effect.
Has anyone tried to connect an antenna other than directly to the u.FL connector on the SOM?

2

The GNSS_LNA_EN pin is somewhat automatically managed by the Neo M8U module. There isn't any other way to connect a GNSS antenna than via the u.FL connector. As long as you provide an antenna that supports L1 bands it should be ready.

3

Thanks Eric!
What is the purpose of the various GNSS pins on the SOM then?
E.g. the GNSS_ANT_PWR and GNSS_RF? Are these just related to the onboard u.FL connector?

4

They are meant for various test fixtures for early TSOM development and manufacturing. We did use GNSS_ANT_PWR in Tracker One to charge up a super capactior for GNSS ephemeris as shown in page 2 of the schematics. The other GNSS related nets are unrouted.