This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
We found this oscillator in a documentation for radio amateurs from the 1970s. The circuit can use...
Many oscilloscopes have high impedance inputs that make it difficult to observe high frequency signals...
This is the receiver for the previous circuit we found in the December 1992 Radio Electronics...