In early 2021 the next version of the SARC WSPR TX commenced after a quick requirements gathering and a “wish list” from club members.   The hardware has been redeveloped by Colin G3YHV who created the first version of the TX. The software has jointly been developed by Colin and Dave G0CJG.  The software now supports Type 1 and Type 2 message formats and controlled by a user setting.

There are a number of options being considered as there no longer any requirement for custom user specific software to be provided, the original unit required the users callsign/locator to be pre-programmed. The potential options are a complete kit (excluding power supply/box) of all components and PCB/PIC Chip only. The documentation is in the process of being updated and will be provided in PDF format.

Latest News

4/4/21 – Design and testing is now complete and components on order. 

9/4/21 – G0CJG/M0KMI working on modifications to the N7DDC auto tuner for QRP input

16/4/21 – Most of the components have now arrived other than the modules coming from the far east!

Detailed below are the features of the Mk2 version of the project and differences from the original TX.

WSPR TX Mk2 Prototype

WSPR TX Mk2 Prototype

  • PCB – move to commercial production
  • Display – upgrade from 16×2 character display to monochrome OLED SSD1306 i2c module
  • Time – replaced UBLOX GPS module with DS3231 real-time clock battery backed module
  • DDS – AD9850 retained due to frequency range
  • PA – upgrade from single transistor to new PA design
  • Power Output – 3 power settings up to 100mW 
  • PIC Chip – 18F1320 8k + 8Mhz oscillator to 18F26K22 64k + 64Mhz oscillator
  • Bands – 80-10 including WARC bands
  • Hourly CW Ident
  • Software – major change from a user pre-programmed configuration to user defined Setup and User menus where all key parameters can be changed/set
    • Callsign
    • Locator
    • Clock (need only be set once unless battery replaced)
    • Single/3 band hopping
    • Output Power 0-23dBm
    • Tune up mode (TX for 15 seconds)
    • Set TX % on time
    • Set Band
    • Set Screenmode (invert display and change brightness)
    • Calibrate DDS
    • Calibrate TX Drive levels
    • Reset all NVRAM settings


WSPR TX Mk2 Prototype