Wednesday, May 26, 2010

--> FM Phone Transmitter

 This project provides the schematic and the parts list needed to construct a FM Phone Transmitter. This device attaches in series to one of your phone lines. When there is a signal on the line (that is, when you pick up the handset) the circuit will transmit the conversation a short distance. In particular it will radiate from the phone line itself. It is a passive device - there is no battery. It uses the signal on the phone line for power. No aerial is needed - it feeds back the RF signal into the phone line which radiates it in the FM band. The frequency of transmission may be adjusted by the trimcap. Note that some countries may ban any electronic device which attaches to the telephone. It is the responsibility of the constructor to check the legal requirements for the operation of this FM Phone Transmitter and to obey them.


download   ckt.  diagram...........

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