Many people have converted a nanoVNA-H4 into a tinyPFA by loading the tinyPFA firmware, see: https://www.tinydevices.org/wiki/pmwiki.php?n=TinyPFA.Homepage For those that are not comfortable with loading new FW there is now a simpler solution. End of this month both Eleshop and R&L will sell pre-configured tinyPFA, ready for use. See: https://eleshop.eu/tinypfa-phase-frequency-analyzer.html The R&L ordering page will be available soon. Erik.