PC-less WSPR project

It is long past time for me to start posting to this blog.  My current project is an Arduino-based WSPR tone generation module.  I am currently using an Arduino Uno along with a DS1307 Real-Time-Clock (RTC) for timing of WSPR transmissions and an MCP4725 DAC.

I am currently breadboarding the circuit as can be seen above and learning a lot about I2C communications programming.  I have basic DDS software written and generating tones using the PWM functionality on the Uno and an external low-pass filter.  I am now moving to a hardware DAC solution.

WSPR encoding and channel symbol generation code has been completed and verified against WSPRCode.exe available from Joe Taylor, the creator of WSPR so I am confident the WSPR generation bits are functional.

Initially, I am using my software DDS code to generate WSPR tones that could be then fed into an SSB transmitter.  Longer term, I plan to use a hardware DDS to generate RF at the transmit frequency for stand-alone beacon use.