Tuesday, February 4, 2014

Spy Bug Fm Transmitter

Spy Bug Fm Transmitter

Click Image to Enlarge

This fm wireless transmitter should only be used for educational purposes.
Regular transmission using such a transmitter without a licence is illegal.
I would like to tell you not to use this for illegal things

This transmitter can deliver signals up to 50 meters. The transistor 2N2222 serves as the modulator 
as well as oscillator. Capacitor 33pf and inductor L1 forms the necessary tank circuit for making 
oscillation. Adjustments in the transmission frequency can be made by compressing or relaxing
the coil. The voice to be transmitted is coupled to the base of Q1 using an electret microphone. 
The FM signal available at the collector of Q1 is radiated using the antenna.

Click Image to Enlarge



Notes.

    Use a 3V battery for powering the circuit.
    The circuit can be assembled on a Vero board.
    Coil L1 can be made by making 5 turns of 24AWG wire on a 1cm plastic former.
    Antenna can be a 25cm long 18AWG wire.




No comments:

Post a Comment