WSPR generation

I have tried out my idea for a WSPR setup. This is an Arduino with a AD9850 DDS generating the transmit carrier, with a DSB mixer attached. The audio input comes from an iPhone app iWSPR. I had to "trim" the DDS frequency up a bit to get it to send at 7040100 (1500 kHz modulation on a 7038600 carrier).





The receive is my recently built SDR. the output goes to the iMac through an FCA202 ADC running at 48kHz. The receiver software is the excellent DSP Radio, and this pipes its audio output via Soundflower to the WSPR program.







The real thing

Now I changed the input to the mixer to come from the WSPR software running on the iMac via the FCA202. Then I switched on the "Upload Spots". The result is, amazingly, this: