We found this circuit in a spy book from the 90s. Transistors admit equivalents and the coil can be designed as in the CB19425E project. Power is provided by cells or 9 V battery.
This shield circuit allows recording of the signal from a serial output on a cassette recorder, with...
This Japanese radio receiver is from the 60s. It has 6 transistors and is powered by 4 batteries with...
The integrated circuit used is a voltage reference from Motorola. This configuration was obtained in...