Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M ohms. Bipolar transistors are general purpose types and the FET supports an equivalent.
We found this circuit in a documentation for 1977 American radio amateurs. The LM336 integrated circuit...
The frequency of this oscillator depends on the coil and the 10 nF capacitor. The circuit is from...
This circuit can work with the previous one generating signals, that can be decoded by it. The...