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During a solar coronal mass ejection, the ejecta generates radio emissions as it plunges through the suns chromosphere and corona. These emissions can be received on earth. There are different types of radio emissions, shown in the spectrogram examples on this page:
Early in the year, I observed a noise pattern in my kiwisdrs spectrogram that coincidentally happened at the same time as a solar flare with CME. I was sceptical, so I haven't thought further about this.
On June 9th 2021, I saw the same pattern again, at the same time of a CME associated to a C3.8 LDE flare, with officially confirmed type-II radio emission.
I was still sceptical if it was really what I was seeing on my kiwisdr.
Here is a spectrogram of the event. Note that I have set the spectrogram very sensitive (low dynamic range) for the purpose of showing background noise. So DSL and PLC noise from more than 50 meters away can be seen. Also I have some LC filters installed, to prevent receiver saturation from strong broadcast stations. WF-rate 1 Hz. Suspected radio emission is circled red:
Below 5 MHz no emission was recorded (on a separate kiwisdr with different filters). But the signal would be attenuated by the ionospheric D-layer anyway, so it can't reach earth surface.
Now, today there was a powerful X1.59 flare. And my kiwisdr shows again this pattern. This time also with a distinctive radio blackout, as expected from a X-class flare.
Since a few other people also tried this, I thought it might be worth an extra thread to share experiences.
For inexperienced users: Updating the kernel might brick your kiwi. Don't try it without a reason.
The how-to for updating the kernel is found here: https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Kernel_Upgrade
Kernel versions I found to be working:
Kernel versions which might cause problems:
LTS44: 4.4.155-ti-r155 (high system load prevents GPS from acquiring satellites, lagging webinterface, seems to be missing firmware)
LTS414: 4.14.108-ti-r108 (doesn't boot)
LTS419: 4.19.50-ti-r20 (does boot, but doesn't work with kiwid)