Small / Compact 1-Chip BA1404 3V FM Stereo Transmitter

Most FM transmitters are very large, expensive and very difficult to construct. Not this transmitter. It uses a single microchip that provides a lot of the circuitry required to broadcast on the FM band. The chip (BA1404) is an integrated stereo FM transmitter that requires just a few external components for operation.

Even better, the transmitter requires only 1.5-3V DC for operation, so it can be powered from just a single 1.5 AA battery, making it ideal as a portable FM transmitter for your iPod, CD players, etc. Note that 3 Volts DC is probably the maximum power supply voltage that should be used (the technical specs show a limit of 2.5 V). Be sure not to power it with your 9-12 Volts or you will likely blow the BA1404 chip.

All-in-all, this is a good first-build FM transmitter. It is possible to use an FM Power Amplifier (well, maybe those aren't the best choice), but please note that you should not broadcast with more power than is allowed by local laws in your country.

The range of the transmitter is not specified, but we're guessing a few hundred feet max. Requires just 30cm (about 1 ft.) of copper wire which acts as an antenna! Circuit schematic and PCB designs are included.