https://forum.arduino.cc/t/rf-explorer-arduino-coprocesor-expansion-board/69958
RF Explorer - Arduino coprocesor Expansion Board - Hardware Development - Arduino Forum
Aug 26, 2011 - Background: RF Explorer is a handheld spectrum analyzer which can be used on all popular ISM bands, to keep this thread short I won't extend much on current...
rf explorerexpansion boardhardware developmentarduinoforum