F5OEO
Kurt, I just made some commits. Can you test with it ? What is your configuration system (Raspbian Lite version Stretch ou Jessie ?) : uname -a
Add gpu_freq=250 in /boot/config.txt should fix the problem
I2S confilcting with rpitx. For Wspr, I set it to use PWM to avoid it. Please test with latest commits (both Wsprpi and librpitx)
Have no issue on with my rpizerow here. Can you try v2beta branch of https://github.com/F5OEO/rpitx and try pichirp for example to check how it workds ? Can you confirm that...
Can you try with gpu_freq=250 in /boot/config.txt
Is it still an issue ?
Try it without HDMI output (headless though ssh) first.
It should be possible to modulate GMSK with rpitx. This is on first tasks I have on TODO list (for other application) . But not sure transmitting AIS with rpitx...
Understand for local testing . As rpitx is I/Q input, you could help me implement GMSK if you like. I figure to use efficient liquid-dsp to do that. Great community...
My AIS knowledge is limited for now...but as soon as GMSK is implemented, get in touch !