Inspired by "Hot Iron" edited by Peter Thornton GW6NGR I see reference to Rick Andersen KE3JJ. He has several very simple designs on his site.
See http://www.ke3ij.com/ .
Simple QRP projects, 10m, 8m, 6m, 4m, FT8, 160m, WSPR, LF/MF, sub-9kHz, nanowaves and other random stuff, some not related to amateur radio.
Inspired by "Hot Iron" edited by Peter Thornton GW6NGR I see reference to Rick Andersen KE3JJ. He has several very simple designs on his site.
See http://www.ke3ij.com/ .
So far today my 500uW has been spotted by 2 stations (see table).