Tips:
1. This motherboard is only used by medium wave wireless lovers, which can test the effect of rock radio.
2. Spare parts: including the components and audio cables on the motherboard, the frequency points need to be adjusted by yourself.
Finished board: usable when power on, including audio cable.
The color of the board will vary depending on the production batch. The function remains unchanged.
Radio sound effects:
http://v.youku.com/v_show/id_XNDQxNDk1NTEzMg==.html
Electrical parameters:
Power supply: 9V2A DC, 5.5 interface, internal positive and external negative (need to bring your own power supply)
Transmitting frequency: 530~1600KHZ (radio medium wave band)
High-frequency transmission power: adjustable 20 mW ~ 500 mW, adjustable power used within 5 ~ 10 meters.
Antenna: Copper wire for 1.5~2.5 meters at home
Audio input: 3.5mm at both ends, attached with board
Audio source: CD, desktop computer, mobile phone, etc.
Application: Medium wave radio enthusiasts, for students to study the principles of wireless signal generation and audio modulation of AM transmitters.
![](https://ae01.alicdn.com/kf/H2f047c0714704c7584c8dc3f8905a358j.jpg)
![](https://ae01.alicdn.com/kf/H22e982baa7d043ac8df18d12bf2718f40.jpg)
The audio amplifier circuit outputs enough audio power to the modulation circuit.
![](https://ae01.alicdn.com/kf/Hcf511034160d4db0a6b334de3f0d07c0r.jpg)
This board adopts collector modulation, has the characteristics of low distortion, adjustable amplitude, and superior sound quality; suitable for radio enthusiasts and student experiments.
![](https://ae01.alicdn.com/kf/H916f664ff1d949eca21573f4d8a96865e.jpg)
Adjust the 223 tuning capacitor, the frequency can be changed between 530~1600KHZ;
Debugging method of spare parts: turn the PVC counterclockwise to the end, adjust the PVC trimming capacitor to the angle shown in the figure, set the digital display radio to 530KHZ, fine-tune the midweek until the signal is received; then adjust the PVC clockwise to the end , Set the digital display radio to 1600KHZ, adjust the PVC trimming capacitor to 1600KHZ, and adjust it back and forth to set the radio to 5300~1600KHZ. It is similar to the method of adjusting the local oscillator of the whole transistor.
![](https://ae01.alicdn.com/kf/Hdf2a3e8708bc49d193d374a263725560P.jpg)
The use and experiment of radio transmitters must comply with local radio regulations, and adjust the amplitude knob to minimize the power.
![](https://ae01.alicdn.com/kf/H14424d6aa35d44bdb1bbf9a67e755e7dV.jpg)
![](https://ae01.alicdn.com/kf/H7788f5ffbce6430b8ab6a72746aed090e.jpg)
![](https://ae01.alicdn.com/kf/Hb06717c1c3974e7d9156cec1cd6e6a67l.jpg)
![](https://ae01.alicdn.com/kf/Hf2860f39935b45048118243cb23890c6r.jpg)
![](https://ae01.alicdn.com/kf/He0c55747f2da4150a023d405846d2a87C.jpg)