This circuit was published in a recent magazine as a past project. It is a crystal radio from October 1986 Radio Electronics magazine. The article detailed the assembly.
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
This power supply can be implemented with a TIP32 providing an adjustable output at the 2k2...
This switched circuit was found in an old documentation and no information about the transformer...