This circuit for monitoring telegraphy transmissions was found in a 1975 CQ magazine. Transistors may be modern equivalents.
We found this circuit in the Radio Electronics magazine of May 1977. The circuit has the frequency...
This 200 kHz oscillator was found on a 90's EDN. It consumes only 2.8 mW and has CMOS compatible...
This tracker for audio and RF signals was found in old American documentation. Transistors and...