Strange as it seems, this circuit can transmit rf Amplitude modulated (AM) in approximately 600 Khz frequency for that he uses an Integrated circuit as 555 oscillator. The audio enters the PIN number 5 of the integrated circuit 555 coming from an electret microphone, an integrated circuit converts the frequency modulated signal to a modulated amplitude and output is on pin 3, where an antenna can be placed directly on it or a coaxial cable.
The antenna must have a length of about 2 to 3 meters, your signal that can be received by any medium wave radio receiver up to a distance of 25 to 30 meters.
List of components
R1 380 ohms
R2 1 Kohm
C1 0.001 mf
C2 1,000 mf x 25 volts
IC1 IC 555 timer
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