Using a sensitive crystal or ceramic microphone, this circuit can pick up faint sounds through a wall. The circuit has a good range given the use of an RF amplifier transistor.
L1 is formed by 80 turns of wire 28 in a ferrite rod to tune medium waves range. The circuit can...
This simple transmitter for the citizen range was obtained in a 1983 publication and has only one...
This circuit can be used with any auio amplifier, converting it into a AM receiver. Antenna is a...