This circuit operates with an AM radio tuned to or near 900 kHz if there is a station at this location. The coil consists of 60 + 40 turns 28 on a ferrite rod.
In the figure we have the way to make the connection of voltage regulators in series to obtain a...
This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time...
This mixer uses only four passive component and can be used with high impedance sources. The input and...