More WSPR on 40 metres

A short break from work gave me some time for more experiments using WSPR over the Easter holidays from my WFH desk with a Raspberry Pi and Yaesu FT-817.

I first tried using a Clansman E-VHF sleeve dipole which happens to work rather badly on 30m and 17m and then with a Maldol 40m mobile whip operating at ground level in the garden.

Despite the simple setup, I managed to be heard in Australia, New Zealand the Falkland Islands.  I've also learned the trick (from a DL) of calling CQ on CW on the same dial frequency which makes you audible at +700Hz whilst remaining outside of the WSPR audio pass-band at +1.5kHz.

Australia on 2 Watts

Extremely happy - Running WSPR on a Raspberry Pi 4 driving an FT-817 with Yaesu  SCU-17 sound card interface, I have been heard in Australia! (Anyone else getting spurious decodes with a similar setup ?)

The  antenna is a MALDOL 40 metre band mobile whip mounted on a clothes dryer spike and a "Clansman" PRC counterpoise...

Although I reported 5 Watts (37 dBm) in the transmission, the AGC was backed off and I have since measured the output power with an RMS meter at just under 2 Watts.  I think it's time to build the QRP Labs Ultimate WSPR/QRSS kit or even a Raspberry Pi transmitter!

Repeat of WSPR Experiment from Barmby Tidal Barrier

To provide a comparison with the previous experiment, the WSPRLite was again setup from the Goole Radio and Electronics Society's portable location at Barmby Tidal Barrier.  Apart from changing the callsign back to G0VRM, the setup was identical.  This time, there was some grayline DX to the Canaries at approximately 8PM, otherwise the results were virtually identical.

WSPR from a Diamond HF-30HX Mobile Whip

Whilst on holiday in Trawsgoed, near Aberystwyth, Wales I setup my WSPRLite using a Diamond HF-30FX 10 MHz mobile whip.  The WSPRLite was configured using the WSPRLite Explorer App using Samsung Galaxy S7, setting the callsign and locations from the phone's GPS, and was left powered from the phone and left running overnight in the car.

Whilst the phone's battery was completely discharged in the morning, the transmitter worked from 8PM until approximately 4AM, and despite the "compromise antenna", contacts into most of Europe were logged.

Arduino Class Libraries for WSPR and SiLabs Si5351 Clock Generator IC

My first attempt at writing an Arduino sketch that transmitted a WSPR message using an AD9850 DDS Signal Generator module, whilst successful required the WSPR message to be generated using the WSPRcode.EXE and then manually edited into the Arduino Sketch before compiling the code.  Ideally, I'd like to be able to read the position and time from the NMEA string from a GPS, encode the message and then transmit it automatically - OK there are niceties such as a User Interface and LCD to contend with! 

Looking back at the Etherkits website, they appear to have a module available which has an SiLabs Si5351 Clock Generator mounted into a breakout, as do Adafruit, however they also supply an easily integrated Class Library.  Until a recent C# online course at work, I didn't really understand what C++ classes did and how to use them, so it's  time to experiment as I've got the example code to compile without error.

I've also got some building to do as I've got some QRP Labs low-pass filter modules to build for 5 and 10 MHz together with a Kanga / M0XPD Si5351 Shield for the Arduino. 

Arduino WSPR Beacon

The idea of building a stand-alone WSPR beacon came about after I built the Silicon Labs si570 based USB-Controlled Synthesizer several years ago and struggled to find a real use for it and was hoping this might be supported in the WSPR software.

Last year I ordered an AD9850 module from eBay and following the example from the web of "Testing an eBay AD9850 DDS Module with Arduino (N8RO)" was able to make it work.  Shorly afterwards I built the Kanga / M0XPD DDS shield and found George M0GEO had already written a WSPR beacon.

Over the last few evenings whilst working away I have combined the two and managed to get it to transmit a message to my FT-817 and decode it using my PC.