This FM receiver tuning step circuit was found in a 1960 documentation. No information about the coils is given, but the FI used at the time was 10.8 MHz.
This antenna for the frequencies 146 or 440 MHz was found in a magazine 73 for Amateur Radio of...
This circuit produces 1 kHz square signals using the CMOS IC 4070. The frequency is given by the...
Found in a 90s PE Hobbyst Handbook, this circuit mimics the sound of a space gun. The components...