FM converter for AM radio

June 22, 1997

The Audiovox FMC-1C is an FM converter (listen to FM radio on an AM-only car radio) from the late 1970s. The user-tunable FM broadcast 88-108 MHz front end downconverts to 10.7 MHz IF, then into a TA7130P IF amplifier / detector IC, that is then modulated to 1.400 MHz AM signal. In effect, the FM broadcast receiver connects to an micro AM transmitter. The AM-only car radio is tuned to 1400 kHz and then tune the FM converter to the desired FM frequency. Even if the AM radio is AM stereo, the FM signal will be mono. The music fidelity is primarily limited by the IF bandwidth of the AM car radio, perhaps 3-6 kHz or so.