This powerful high-fidelity amplifier was described in an article in Radio Electronics magazine in December 1973. Note the use of 8 high-power transistors that must be mounted on excellent heat sinks.
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...