This circuit uses a 555 (according to the diagram) to generate 50 ms tone bursts at a frequency of 1.5 kHz. The circuit is from an 80's Electronic Design.
This circuit can be used to detect the signals from the previous circuit or from any radio...
Found in Popular Electronics from the 90's, this circuit makes use of components from the time. |...
This receiver for frequencies up to 18 MHz was found in American documentation from the 1990s. Data...