Occasionally intersting projects do get shown on the BATC QO100 net which runs on Thursday evenings.
One such occasion was when GI4DOH mentioned he was using a cheap A to D board in front of a commercial FPGA board to do cw skimming and rtty skimming instead of the expensive Red pittaya board
I had been using my ANAN 10 to do my skimming which is overkill . It is limited to 4 receivers. His system could do 8 so time to Investigate!
Full information was available at https://pavel-demin.github.io/qmtech-xc7z020-notes/ who was the designer of the A to D board. All the necessary files were available to get the boards assembled in China. Luckily i found someone who was getting a batch made so i ordered one from him. The cost (shipped) was £58
The FPGA board QMTECH ZYNQ7000 XC7Z020 Development Board was available from Aliexpress for around £80. It came with a 5 Volt Power supply
The only other items needed were a 2x25 pin header and socket to mate the boards, a heatsink to keep the FPGA from overheating and an edge mount SMA socket
The A/D pcb has a reminder to remove R14 and R15 on the FPGA board before mating the two boards and to connect 3.3V wires between the 2 boards, It didnt take long to put together
Software was easy. Format an SDHC card then copy the contents of qmtech-adc-20240614.zip to it. I also copy the start.sh from sdr_receiver_hpsdr_77_76 directory to the root directory so that on power up the receiver can be accessed by HPSDR
After power up I found the ip address assigned by the router and pointed HPSDR running on my PC . It connected and I could see signals
Overnight i compared the 600m WSPR decodes on the new receiver with the 600m WSPR decodes on the ANAN-10. They were within 1dB of each other , the new receiver has good sensitivity
Next task is to get it skimming!
