We found this sophisticated meter circuit in an article in Radio Electronics magazine from June 1959. The article taught how to assemble it. Transistors are common types at the time.
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...
The LM387 integrated circuit used in this project is not very easy to obtain. The circuit, from an...
The recommended distance between the emitter and the sensor of this coupler is 15 mm. The circuit is...