Desktop WSPR

Just to see if my software works, I am sending WSPR messages across my desktop! I cannot send them out into the ether as I do not have a LPF on the transmitter/VFO and there are tons of harmonics at the moment. Anyway the VFO output is only a few milliwatts, so I don't think I would get far with my small stick aerial.

Here's the set up. The transmitter is an Arduino Uno with the VFO shield (described previously) mounted on top, I have a 6" piece of wire as an antenna on output "G0". The receiver is also an Arduino Uno with another VFO shield and the SDR shield on top. The antenna is a, very inefficient, Wonder-Wand.



iMac running both HDSDR receiver software, Soundflower to send the audio across to WSPR software. HDSDR is running under Wine on the Mac as it is a Windows program, WSPR is native to OSX.



This is the transmitter LCD display. The code being sent, hardcoded into the Arduino sketch, is shown at the top (Call, Locator, Power). The Interval between sends is 2 min shown bottom left, this can be changed by pushing the encoder button to 4, 6, or 8 min. The frequency of the transmission is set to 7040.100, but can be tuned in 10Hz steps by the encoder.


And the SDR receiver display. This show the time at the top, the SDR centre frequency and the 40m band plan for this frequency at the bottom.



The Screen shots of HDSDR and WSPR. HDSDR is tuned to 7038.600 to have an output of 1500Hz from the received WSPR signal. This is fed to the WSPR program and should display at "100" on the scale. As you can see either the transmitter or SDR are about 50Hz off frequency - neither has been calibrated.





Fun and it works, which at least shows the software on both the TX and SDR Arduino is OK.