VK3YE One Transistor CW Transmitter
With a tip of the cap to Peter Parker, VK3YE, the above video has some excellent information. A generic homebrewer typically has a plan to do something but quickly and inexpensively. The Reverend George Dobbs (SK) would call for a one a done as the template. The idea is to take one evening and build something and you are done.
Peter shows how a transmitter can be built using less than a dozen parts and is capable of being heard 2500 Kilometers distant. The power output as VK3YE demonstrates can be greater than 1 watt.
But there are no free lunches, and the Chirpy part is real. The chirp is somewhat mitigated by using a larger size crystal. The HC49/U type are small and subject to heating. Switching to the HC6U not only cleaned up the signal but the power output was more consistent. Not to be taken lightly is the need for a post rig filter (W3NQN) between the output and the antenna.
As was indicated the three-winding coil has to be diddled with for maximum power transfer. So, unless you are extremely lucky that effort may take more than 39 seconds.
I want to also mention Peter's use of the SDR receiver sites (also keep in mind the reverse beacon network) as a tool for his rig development.
Peter's work was an implementation of a design by SV3ORA intended for emergency use which was modified by VK3YE.
My sharing this info is in hopes that others would be bitten by the homebrew bug and using solid state devices simplifies the power supply (and safety) issue. As Peter said almost any old NPN transistor would work and there are no exotic (or expensive) parts in the build. The Coil is the only piece that may take some development time. But as he cleverly did, he wound the two smaller coils first so he could adjust the turns of the larger coil.
Them that know can make things go.
73's
Pete N6QW