Hi David (@David_Jensen ),
The Postcard has the Quectel LG290P GNSS module on it. The “How to Build a DIY GNSS Reference Station” tutorial was written for earlier products based on the u-blox ZED-F9P. Your approach will need to be different for the LG290P.
Please tell us more about your setup. From another post, it sounds like you bought both Postcards and Portability Shields? What do you have connected up on the roof - Postcard or Postcard+Shield?
If it is Postcard+Shield, you may want to log the data to the Shield SD card using our RTK Everywhere firmware. If it is just Postcard, you’ll need to log the data on your mini PC.
u-blox u-center isn’t going to work for you. Quectel have their own software called QGNSS. But there are 3rd-party open-source solutions like PyGPSClient too.
Regarding which messages to log, the post linked below should help. It’s a long read but there’s a lot of good stuff in there.
I hope this helps,
Paul