The Hermes Lite 2 is completely open source (from circuit board layout to FPGA gateware code, etc.). http://www.hermeslite.com It's a direct sampling HF transceiver with an ethernet connection (serves IQ over UDP). 5W tx. If you don''t want to build from scratch, nearly finished units (loaded tested PCBs) are in production: https://www.makerfabs.com/index.php?route=product/search&search=hermes It's fairly inexpensive (half the price of an mcHF clone). I just received my 2nd HL2 yesterday. I use these SDRs to experiment with writing my own SDR code (from first principles) that runs on Raspberry Pi's, iPhones and iPads.