Radio receiver using the ZN414

This project originates from the past and has demonstrated significant success. It serves as the foundation for an 8-channel proportional R/C (AM) and 145MHz FM chat box. The receiver design is straightforward and includes a single transistor mixer followed by a ZN414 radio integrated circuit (IC) for gain and detection. An OP-AMP 741 is utilized as the final audio stage, which can be substituted with an LM380 for driving a small speaker.

The described project involves an 8-channel proportional radio control (R/C) communication system operating on AM and FM frequencies, specifically at 145MHz. The core of the receiver circuit features a single transistor mixer. The mixer is responsible for combining the incoming radio frequency (RF) signal with a local oscillator signal, enabling the demodulation process to extract the audio information from the carrier wave.

Following the mixer, the ZN414 radio IC is employed, which provides both amplification and detection functions. The ZN414 is a low-power, integrated radio receiver chip that simplifies the design by integrating essential components, such as an oscillator, mixer, and demodulator, into a single package. This IC is particularly useful for low-frequency applications and is well-suited for this project due to its compact size and efficiency.

The audio output from the ZN414 is then processed by an operational amplifier (OP-AMP) 741, which serves as the final audio stage. The OP-AMP is configured to amplify the weak audio signal to a level suitable for driving a speaker or headphones. The choice of the OP-AMP 741 can be modified; if a higher power output is required, an LM380 can be used instead. The LM380 is a power amplifier capable of delivering sufficient output to drive small speakers directly, making it a suitable alternative for applications requiring enhanced audio performance.

Overall, this circuit design provides a robust and effective solution for an 8-channel proportional R/C communication system, combining simplicity with functionality. The use of readily available components such as the ZN414 and OP-AMPs allows for easy construction and flexibility in application, making it an excellent choice for hobbyists and enthusiasts in the field of radio communications.This is a project from the dim and distant past that has proven to be a real winner. I have used it as a basis for an 8 channel proportional R / C (AM) and 145MHz FM chat box. Recipients very simple and is shown below. This consists of a single transistor mixer then ZN414 radio IC to provide the gain and detection. An OP-AMP 741 is used as the final audio stage, but it can be replaced by LM380, if you want to drive a small speaker 🔗 External reference