I wonder if QRP would be something? https://hackaday.com/2016/03/08/how-low-can-you-go-the-world-of-qrp-operation/ https://hackaday.com/2016/03/08/how-low-can-

I wonder if QRP would be something? https://hackaday.com/2016/03/08/how-low-can-you-go-the-world-of-qrp-operation/ https://hackaday.com/2016/03/08/how-low-can-you-go-the-world... also https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) https://wsjt.sourceforge.io/wsjtx.html https://wsjt.sourceforge.io/wsjtx.html plus the super simple "Fireball QRP transmitter" https://www.worldradiohistory.com/Archive-DX/73-magazine/73-magazine-1990/73-magazine-11-november-1990.pdf https://www.worldradiohistory.com/Archive-DX/73-magazine/73-...