Shipping hardware internationally is a hard, labor intensive, and overall a frustrating process - especially more so these days.
Here is our plan to supply the DDX to customers:
Make the hardware part free (Free an in Freedom)
The users will be able to order fully assembled boards from JLCPCB or other vendors on their own.
Required a small licensing fee for the software firmware part
This is how we get to keep the hobby self-sustaining!
Future DDX architecture ideas (from Ismo and other folks):
Antenna ➔ CD2003 ➔ 455 kHz IF ➔ Ceramic filter SMD (HCI) ➔ Pico 2's ADC ➔ Down-conversion and processing in digital domain ➔ Expose the processed audio samples over USB (Pico 2 acts as a sound card).
Benefits: This enables reception of SSB and CW signals!
We are planning to try STM32H5 for this new DDX architecture!
Alternate easier and traditional radio architecture:
Antenna ➔ CD2003 ➔ 455 kHz IF ➔ Ceramic filter SMD (HCI) ➔ Mix with BFO ➔ "Some detector" ➔ Direct Sound output ➔ Pico 2's ADC ➔ Pico exposes the audio samples over USB