Dispelling the mysteries of radio. A series featuring a variety of practical circuits for the set builder and experimenter. This month: A highly sensitive receiving system and buffer amplifier.

This month we consider the technique known as super-regeneration. No other radio circuit, it is claimed, produces more gain from a single valve or transistor. Readers who have access to a Frequency Counter may wish to use it as a digital readout dial for the Regenerative Receivers covered in Parts Three and Four, and the Direct Conversion receiver to be described later in the series.

Details of a simple buffer amplifier for linking receiver to counter are given this month. Last but not least, before we tune-in to the subject of super-regeneration, readers may care to build the simple low-cost Crystal Marker calibration aid also described here. This is aimed particularly at last month’s amateur bands receiver.