Simple FM Radio Using LA1260

This project implements a classic superheterodyne FM radio receiver built around the LA1260 dedicated radio receiver IC and a BF494 RF transistor. Operating on a compact 5cm x 7cm Veroboard, the circuit uses a 75cm wire antenna to capture frequency-modulated radio signals from the air. The incoming RF signal is fed into the front-end stage featuring the BF494 transistor, which handles initial amplification and mixes the signal. The LA1260 IC then takes over the core superheterodyne processing, which includes intermediate frequency (IF) amplification and demodulation. A 5.5MHz IFT coil and a matching 5.5MHz 3-pin ceramic filter are employed to establish the specific intermediate frequency stage, ensuring precise channel selectivity and filtering out unwanted frequencies. Tuning is managed by a variable 2-22pF trimmer capacitor alongside fixed capacitors and resistors (such as the 470K, 6K8, and 470 ohm variants) that set the necessary biasing and time constants for stable operation. Decoupling and coupling are handled by various capacitors, including 10uF/25V and 1uF/25V electrolytics as well as smaller ceramic disks like 102 and 103 codes. Once the LA1260 successfully demodulates the audio information from the 5.5MHz IF carrier, the resulting audio frequency (AF) signal is outputted to an external AF amplifier and speaker system so the broadcast can be heard clearly. The entire analog system runs reliably on a modest +6V DC power supply.