I had found a similar article about making the antenna a dipole. The interesting thing the article stressed was the lengths of the wires. I'm not an antenna engineer (my brother is) so I made the wires as suggested. I think it made a small improvement. and I still use that radio.
My advice on antennas is: don't modify it. If your application needs more range, you're going to need more power. Signal strength drops off with the cube of the distance. So you're going to need a better antenna. For $3 (and a month or two delivery time) you can get a theoretically better module+antenna
I was wondering the kind of modification needed to support ATMEGA4808/4809.
I have read again the MyConfig.h and MySensors.h, they look quite good.
Though, there might be some updates to be done in the hal/architecture/AVR folder ..
@OldSurferDude I am not sure what the real difference between c/c++ code with the Arduino libraries, and c/c++ code without the Arduino libraries. But I don't think there is much difference. it is still code, and it is possible to add other libraries as well. So if your code needs any libraries, you should be able to include them like you would normally do.
From what I understand, the MySensors hardware abstraction layer for rpi includes an emulated EEPROM. So you can use the Arduino EEPROM stuff if you want to, or just use plain c or c++ code to write to a file.
For nodes, it is possible to force node id by setting MY_NODE_ID. However, a MySensors gateway always has node id 0 so this is not applicable for a gateway. You would not need to write any code that saves and restores the node id.