FM/AM/LW/SW SSB/USB Radio Project with SI4735

It’s possible to make digital radios very easily with SI47xx and SI48xx series radio chips, which are widely used in professional broadband digital radios.

I selected the SI4735 (SI4735-D60-GU), which is the full digital chip of the series. Speaking of digital, popular Arduino, STM32 or ESP32 / ESP8266 development boards can be used to control these chips. In this example, I used the ESP32 Wifi card. Although it has wifi feature, I did not use that feature, I only preferred it because it is 32bit and has large memory.

Although these chips normally have SSB feature, but this is not documented and only radio manufacturers (Teksun, Sony, etc.) are given these firmware decoding codes. However, a Russian amateur managed to decode the SSB encoding of the SI4735 chip. I used this SSB patch in my radio project.

I used Si4735 Arduino library published by PU2CLR.

The Arduino sketch and schematic used can be obtained from the links below.

• PU2CLR Arduino Library https://github.com/pu2clr/SI4735
• PE0MGB – schematic and ESP32 sketch https://github.com/pe0mgb/SI4735-Radio-ESP32-Touchscreen-Arduino

Required parts:

• SI4735-D60 chip — Aliexpress (China) / Arrow (US) / eBay (UK) / eBay (China)
• If you have difficulties solderin the chip. SOP28 0.65 converter adapter (For Si4725) — Aliexpress
• ILI9341 Touch Screen LCD — Aliexpress
• ESP-32s Development Board — Amazon Aliexpress

Other examples:

• https://pu2clr.github.io/SI4735/extras/Third_Party_Projects/
• STM32 version https://www.youtube.com/watch?v=6HMdZY_vLmQ
• https://www.hackster.io/pu2clr/all-band-receiver-with-ssb-support-using-si4735-6d6149
• https://www.youtube.com/channel/UCGJZoB78RT6wmeEeRpZzi7w
• https://github.com/RSZ-Nld
• https://www.youtube.com/watch?v=NPaUZSP8ouo

Si4735 Breakout Boards

• https://github.com/RSZ-Nld/Si4735_Display (With touch screen module) >> PCBWAY Gerber
• https://github.com/RSZ-Nld/Si4735 (With small screen and buttons)
• https://github.com/LadyRoninEngineer/Si473x