This board wasn't created in a vacuum, and it wasn't created all at once. This is the 4th spin of the board, actually, and most of the previous versions used entirely different architectures and parts. Here's the first version:
It's old! It also didn't work at all.
This one was better, but it had seperate TX and RX paths, so needed 2 antennas.
Getting closer. A bunch more changes, and this is basically the current version, minus a few tweaks and fixes.
This is/was the first RF board I've ever done, so I'm learning as I go!