Debug-free FM transceiver circuit composed of BA1404 TDA7021

The biggest feature of this circuit is that it is simple to make and does not require debugging. In particular, the receiving circuit does not use double variable capacitors and intermediate frequency transformers. The circuit is ready to be assembled, which is very suitable for radio enthusiasts to make their own. Figure (a) is the receiving circuit; Figure (b) is the transmitting circuit.

When the circuit transmits a signal with a frequency of 88 to 108 MHz, L2 is wound with Φ0.65 mm enameled wire into an air-core coil with an inner diameter of 8 mm and 10 turns. L3 is wound with Φ0.65 mm enameled wire into an air-core coil with an inner diameter of 6 mm and 8 turns.