This different circuit was patented and described in the Radio Electronics magazine of March 1958. In that section it used to present different configurations that received patents.
Found in Radio Electronics from the 90s, this circuit converts signals from the 9.5 to 9.8 MHz...
This circuit was found in a 2000 documentation. The circuit generates a sequence of notes...
This small transmitter with 2 transistors can reach several hundred meters using a 30 to 70 cm...