Today I received a permit for experimental transmissions on the 500 kHz band, 501.000 - 504.000 kHz.
Now I will need to build a transmitter, I will most probably go the way Joachim proposed, using a 27 MHz crystal on the fundamental frequency (9 MHz), then dividing by 9 with a 4017, then by 2 with a flip-flop, followed by a "buffer amplifier" , and later an IRF510 as power amplifier.
The hard part will be the antenna, it needs to be compact, so a "magnetic loop" is probably the only way to go here.
QRP-LABS 5Watt PA - I am still struggling to make a "simple" 5Watt PA for the 1.8 - 50MHz range The QRP-LABS 5W PA could not deliver more then 1W at 28MHz using the original...
6 minutes ago