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Quote..... "NanoVNA is a very compact and portable vector network analyzer created by Mr. TAKAHASHI Tomohiro(edy555), which cost is very low. It is easy to manufacture and provide good measurement accuracy. Mr. Takahashi uses the GPL protocol to open source the NanoVNA software, aiming to attract more young people to pay attention to radio frequency and wireless. Based on Mr. Takahashi's software, I made simple modification to make it measure with odd harmonic. What's more, I have made a version that can measure 900MHz and shared it in the community, which has received widespread attention from the community. Later on, I started to mass produce NanoVNA. At the suggestion of Mr. Takahashi, I renamed my version NanoVNA-H. The community began to contribute new code for NanoVNA, new features were added, cho45 added TDR and screenshot functions to NanoVNA, and QRP73 helped to improve the driver of Si5351 and AIC3204. With more functional requirements being raised, the resources of STM32F072CBT6 are not enough, therefore, under a discussion with Mr. Liao(AA6KL) at /, he proposed the idea to replace STM32F303CCT6 with STM32F072CBT6. I provided Mr. Liao a NanoVNA-H test version with STM32F303CCT6. Thanks to Mr. Takahashi's early work, the porting was smooth. Because the STM32F303CCT6 has a faster SPI bus speed, we started to consider the display size problem which is widely complained by the community. After some selection and testing, we finally used a 4-inch LCD screen. After discussion with Issues # # 14, we have now increased the measurement frequency of NanoVNA to 1.5GHz. With the larger screen, we have more PCB space for components and batteries. Therefore, we use a separate charge pump to power the mixer and add tantalum capacitors, which can further reduce power supply noise, and the 1950mAh battery can be used independently for more than 8 hours. We add DC dimming to the 4.0 inch full-view LCD screen, which make the view more clearly when used outdoors and more comfortable when used indoors. In order to make it easier for geeks to create more possibilities, UART1, PC14, and PC15 are introduced on the PCB. Thanks to the manufacturing experience of NanoVNA-H, we made a new ABS shell for NanoVNA-H 4, which can effectively protect SMA connectors and switchs. Each set of NanoVNA-H 4 sold to the community is installed with a complete ABS shell. It is packed in a beautiful gift box, which can surely protect the NanoVNA-H 4 without being damaged during the long-distance express transportation. NanoVNA-H 4 maintains high degree of software compatibility with previous versions of NanoVNA. All software developed for NanoVNA can be used directly. Just note that with the larger LCD screen, the data returned by the ¡°capture¡± command is twice as long as the original one, but the developers can easily modify the code for compatibility. I'm selling the full NanoVNA at gen111.taobao.com, if you are an overseas user, you can purchase the hardware I made through alibaba. If you need to trade with PayPal, please contact Maggie through Alibaba. you can also design your own PCB by reference schematic, it should be noted that analog circuit partial shielding and isolation are important, the bridge part is strictly matched, if you need to use harmonic extension 300M or more measurements need to pay special attention." |