Simple Radio Microphone 88-108 MHz FM Transmitter - DIY Kit

Simple FM radio transmitter DIY kit. Requires soldering. Any standard 80MHz-108MHz FM radio receiver can be used.

The transmission frequency of the circuit is around 90MHz. Using ordinary FM radio receiving equipment adjust the transmission frequency by slightly changing inductance L to avoid local interferences with local broadcasting radio frequencies.

The working voltage of the circuit is DC 3V-6V. Transmitting distance should be around 10 meters in open space. The distance depends on power supply voltage, antenna length and impedance as well as any obstacles, electromagnetic interference and sensitivity of the receiver.

You can use a wire as an antenna. The antenna should not be too long to avoid affecting the frequency stability.

Technical data:

Frequency range: 80MHz-108MHz
Working voltage: DC3V-6V

CR2032 Battery not included.