This fm transmitter circuit is very simple and it has a acceptable transmission . The signal transited from this fm transmitter circuit can be received at almost 300 meters in open air .
The circuit require a 3 volts operating voltage and can be tuned anywhere in the FM band.
The coil should be about 3mm in diameter and 5 turns. The wire is tinned copper wire, 0.61 mm in diameter.
Using the TDA7021T integrated radio receiver circuit can be designed a very simple high efficiency portable radio receiver circuit fully compatible for applications using the low-voltage micro tuning system (MTS). The TDA7021T has a frequency locked loop (FLL) system with an intermediate frequency of 76 kHz. The selectivity is obtained by active RC filters. The only function to be tuned is the resonant frequency of the oscillator.