GNSS Correction Data Receiver (NEO-D9S) Hookup Guide
bboyho, 
PaulZC 
NEO-D9S and NEO-D9C > Example 1: NEO-D9S
From the menu, select the following: File > Examples > Examples from Custom Libraries | SparkFun u-blox GNSS v3 > NEO-D9S_and_NEO-D9C > Example1_NEO-D9S.
Adjust for Region
By default the example is set up for the US SPARTN 1.8 service. To adjust for Europe, simply comment out the frequency for the US and uncomment the frequency for the EU at the top of the example code using the syntax for a single line comment (i.e. "//").
language:c
const uint32_t myLBandFreq = 1556290000; // Uncomment this line to use the US SPARTN 1.8 service
//const uint32_t myLBandFreq = 1545260000; // Uncomment this line to use the EU SPARTN 1.8 service
Upload Code
When ready, select the correct board definition from the menu (in this case, Tools > Boards > SparkFun ESP32 IoT RedBoard). Then select the correct COM port that the board enumerated to (in this case, it was COM13). Hit the upload button.
What You Should See
Open the Arduino Serial Monitor at 115200 baud. If all is well, you should see the following output indicating that the UBX-RXM-PMP correction data is being received! In this case, the NEO-D9S had a multiband antenna pointing up towards the sky from SparkFun HQ's rooftop.
