This circuit was suggested by General Electric in a 1969 documentation. The transistors are of the time and the power supply is not given. Note the high supply voltage.
This circuit with automatic gain control was found in the July 1988 issue of Radio Electronics magazine....
The microwave sensor of this circuit is a common ceramic capacitor. The circuit is from an 80's...
This receiver was found in an article in Electronics Now magazine in March 1994. The coils are...