No, not at the moment. So far this is just a private hobby project.
Absolutely. All required files are available and if you are not afraid to solder a lot of small components you can certainly build your own. The total BOM cost (without the aluminium shielding) is about 200€ when only buying parts for one PCB.
There are some basic instructions to help get started on the software side.
I am using 250kHz as the final IF frequency. Compared to some other VNA projects this is rather high and requires a fast (more expensive) ADC. However, it also makes the sweep rate faster: each measurement point takes at least one IF period (more if noise should be reduced to practical levels).
Why not sample the ADCs directly with (a more powerful) STM32? Or even use the ADC on the µC itself?
- I wanted more than the 12bits provided with by internal STM32 ADCs (and also better SNR)
- Sampling the three 16bit 1MSamples/s ADCs with an STM might be possible but certainly would be a challenge
- More flexibility with the FPGA controlling all critical RF components (e.g. setting up all PLLs concurrently for each measurement point, further increasing sweep rate)
- Enough power for future features (e.g. spectrum analyzer mode with FFT)
- Sorry, thats just what I had experience with (also, the toolchain is free, just not open-source)