nobcha23のエアバンド受信機自作ブログ DIY airband receiver BLOG

エアバンドレシーバーキットの組み立て、改造を手掛けます Assemble and remodel Chinese airband receiver kit

Introduction to homemade air band receiver (4_4) R909-DSP(Si4732+Si5351a)

(This material is translated version.)


The last radio I will introduce is R909-DSP. This receiver was designed and sketched by myself based on Jason's idea of the R909 receiver. I thought it worked for the time being, but there were some issues and items that were not achieved and I'm continuing to consider them.

Ever since I started this blog, I've been thinking about making an airband receiver using a DSP chip. This time it finally happened. The configuration is TA2003-Si5351a-Si4732-LM386.

When receiving Airband, the local oscillator from the Si5351a module is input to the TA2003 first-stage mixer section and converted to IF21.4MHz, and the Si4732 operates as an AM21.4MHz receiver. FM broadcasts are directly received by the Si4732 chip. For control, use ATmega328P with ARDUINO UNO loader installed. The operating style uses a rotary encoder and switches to select functions, set parameters, and memorize parameters by double-clicking the switch.

The block diagram of R909-DSP

This receiver has two boards. The CPU, operation switches, and OLED are mounted on the PANEL board, and the front end, Si4732, LM386, and Si5351a modules are mounted on the RF board.




The PANEL board alone can also be used as a digital VFO for modifying analog station receivers, etc., and an additional Si5351a module can be mounted on the PANEL board. I also created a DEBUG-PANEL board to which WE1602A can be attached during debugging. This debug panel board was used to convert the Chinese Airband receiver kit (No. 1) into a digital VFO. The OLED display is at the limit of the ATmega328P's memory capacity, so the 1602A display is easier to use when tinkering with sketches.

Remodeled the Chinese airband receiver kit

Furthermore, the RF board has a pin header that allows you to add an ADX front-end filter board to the front-end section. I'm thinking of experimenting with an HF band DSP receiver in the future.

I have uploaded the related data of the three types of boards explained above and the current version sketch of the receiver to GITHUB.    

As an example of how to use it, I have uploaded it to YOUTUBE.


In addition, the width of the RF board has been made 83.5mm so that the RF board can be slid into the drawn aluminum case. In that case, combine it with an OLED version panel. The front and back panels of the case are made from circuit boards, making it neat and compact.


Selling case on Aliexpress