Modifying high performance FM transmitter with FM tuner

Modifying high performance FM transmitter with FM tuner

Recently, I used a damaged FM head to make an FM transmitter. It is very interesting, so I made a close-up to share with you.

The FM head used is a Mizmi FM head, of course, other FM heads with local oscillator output can also be used. Because only the local oscillator part is used during production, it does not matter even if the high-frequency amplifier and mixing are damaged. And in actual use, the FM head local oscillator is rarely damaged. Therefore, some damaged FM heads can be used for production.

Using this Mizimi FM head, the FM transmitter is shown in Figure 1. Just remove the components on the original head and add some components as shown in Figure 1. Use a 50cm rod antenna for the antenna, or a soft wire. Use high-precision components for VD1 and VR1 to ensure frequency stability. After welding. Input the audio signal of the VCD at AUDIO. Then use an FM radio (preferably digital) to find a frequency without local radio stations within 100MHz to 108MHz. Then turn VR1 to receive the signal, and then adjust VR2 to make the volume appropriate without distortion, so that you can listen clearly with a portable radio within a range of 20 meters. And if you touch the transmitting antenna with your hand, its frequency will not change at all. It can be said to be an FM transmitter with excellent performance.

If you want to make an FM wireless microphone, just add the circuit in Figure 2 to make it a high-performance wireless microphone. You can also refer to the previous article of "Electronics News" to connect an external power connector to make the transmission distance longer.