This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics magazine. The source must be symmetrical. The capacitors can be changed for other frequencies.
The circuit shown is from a 1993 documentation. It uses two FETs in an oscillating configuration that...
This output step with a transistor can be used in experimental radios and intercoms or as a signal...
This circuit, for bands above 15 MHz, was found in an Argentine publication from the 1970s. The L1...