[William Dillon] is finishing up his degree. His final project as a student was to design an RF transceiver. He decided to work with the Microchip MRF49XA, which runs around $3 but will cost you $20 if you want it in a ready-to-use module. He didn’t find a lot of info on the Internet about communicating with these chips so he’s shared his design, code, and board files. If you’re ever wanted to delve into RF design this is a good primer. [William] talks about building around the example circuit from the datasheet but also includes a discussion of the calculations he made in working with the 434 MHz band, and an AVR-based library for using his module.