SV1ONW's blog

This is a homebrew Si5351a PLL coupled directly to my GP-3 antenna (modified for 20-17-15-10 meters operation) and controlled from an Arduino Nano with an SSD1306 OLED and using a RTC board for timing.
The station is using the very fine firmware of W3PM, Gene Markus, under the name of WSPR Multifunction Project, that was originally published at QEX July-August 2020 issue.
You can get this excellent code @ Github/W3PM. All credits naturally go to Gene.