Rather than use the microphone input I have been running Fldigi into the USB and having some nice QSOs on Olivia. Olivia has amplitude modulation of the envelope (unlike wspr or ft8) due to how the individual tones are sent. It is not just a simple FM MFSK signal and really needs proper SSB modulation to work as designed. Looking at the time domain on my scope the envelope is just as it should be with fluctuations in amplitude during tone transitions.?
?
When I run calibration of either the QMX and QMX+ using Putty I get a lot of flat lines and incomplete graphs. It does feel like the process is working as it should. I suggest adding some hand-holding messages to assure the user of proper completion. Based on comments above I will try doing the calibration stand alone.
?
I have monitored the transmit signal using an SDRPlay RSP1A and Steve Andrews' free RSP Spectrum analyzer software. I used that to check both two-tone IMD and also unwanted sidebands on an Olivia signal. When I look at the two-tone IMD spectrum I see improvement with the phase compensation ON on some bands and improvement with it OFF on others. For now I am leaving it off and will wait to see how things develop. Amplitude compensation has only minor effect as expected. Unwanted energy from the transmitter is at acceptable levels for now.
?
It's worth noting that using the same measurement methods I can see substantial improvement (~ 15 db) when using the Pure Signal feature of the Hermes Lite 2 through a linear amplifier so I know this technique can show a good effect.
?
For right now I am thrilled to have SSB mode so I can transmit proper Olivia and will take the QMX with me to the UK for portable ops. Down the road it would be nice to set receiver bandwidth as with cw but for typical digital signal bandwidths.
?
Thanks for all the hard work, Hans!
Jim AJ8S