fm transmitter

Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and is therefore a good, useful [...]

The important part of the circuit is formed of the Colpitts type oscillator. C3,C4,C5,C6,CD1-CD2 and L1 determines the frequency. BF982 and dual gate MOSFET are active parts in oscillator. When the input impedance of the MOSFET gate inputs are high, LC tank is not affected. However transistors force the LC tank and cause phase shift.
Two [...]

This is a well designed basic FM transmitter that you can easily recive the signals transmitted from this transmitter in a 1-2km range with using a normal FM reciever. Another property of this circuit is that the bobin is placed on the printed circuit board. The input sound’s amplitude can be adjusted by using the [...]