Congratulations @BearWithBeard, that's a great achievement, especially from someone supposed to be a "novice". I'm sure many can learn from your lessons, the most important one to me is "don't rush it", it goes with "triple check schematic then board", "unit test your components" and "don't finish late at night". Else you will probably end up with mistakes on PCB and a lot of wasted time. For reverse polarity protection, I think this is the more simple solution: https://forum.mysensors.org/topic/5478/how-to-get-longest-battery-life/25

hello! can you advice how flash this fw in arduino ide with avr isp? not work with atmega without crystal yet

Forgot about this guy... Updated the project a little, the PCB now have footprints for both normal and PA+LNA modules. The old boards are still available on the github repository if needed. Even with the extra length added to the PCB with the dual footprint, it is overall still smaller than a regular non SMD NRF24L01 module.

@EddyG PCB received and tested, new version (v1.1) available here and on github.

Okay, finally got the original nrf24l01 SMD modules with the square chip visible... As exptected, things work just fine now, so the culprit of my issues was really the incompatible/fake "nrf24l01" SMD modules with the epoxy blob. If you want to use normal nrf24l01+ modules together with this smd gateway, DO NOT USE the smd module with the epoxy blob, as they won't work. Using only the fake SMD modules might work, too, but mixing the fake modules with real ones does not work.

I have been using an old(cheap) wall-to-USB power supply. I'll give it a try with a beefier supply and let you know the results I get.