The first build of firmware is done and only minor tweeks should be needed. Tested with a STM32F4Discovery board. The driver for the ADF7021-N should be complete and verification via logic analyzer indicates it should bring up the transceiver and go into RX mode. I've added a PTT input definition to one of the many extra pins. Pressing the PTT will transmitted "Hello World" in the first frame and a AMBE audio snippet afterwards saying "Hello World". The OLED display works great even for its very small size. Bright and easy to read low power budget. The Neo GPS module I've used before and I have embedded its output in the last data frame thats sent. Made some small modifications to the new STM CUBE library as it never quite works the way you want it to.