This 5.1 MHz circuit was found in a 1980s documentation. The frequency is given by the crystal and general purpose transistors can be used.
With this simple circuit found in an American 1980s documentation, it is possible to determine the...
This page shows a crystal oscillator for 2 MHz. Other frequencies can be produced depending on the...
This is a converter stage found in old transistor superheterodyne radios. The circuit is for...