This circuit was found in an American 1980s documentation. The transistorized step is the receiver's last IF and the diode is the receiver's existing detector.
We found this circuit in a 1968 Electronics World. The transistors are from the era and...
This circuit, which generates a linear sawtooth signal, can be used in a frequency-band...
The instrument of this field strength meter, from a 1970s publication, can be a 200 uA...