@karelsmits I'm afraid I don't know enough about the hardware to answer. I didn't have any luck with the RFM69 on the Nano, so I switched to the 3.3V ProMini. I used a Moteino USB for my serial gateway. It's a more expensive option, but it was easy to implement and has been very reliable.

How did it go?

@karelsmits this is rather off topic. I suggest you move that question to a different thread as it has no relation to signing or security.