Intermittent waterfall oddities after BBB->BBAI update

cathalferriscathalferris
in BeagleBone AI
After updating to the BBAI Tuesday evening, all appeared to be okay.
However, when I accessed the Kiwi when I was in work, I had static audio and saw the waterfall looking like this:
image
WSPR decodes and uploads from the Pi4 listening to the same Kiwi appeared to be still working away and the noise graphs on Grafana for swljn47fj station still appeared somewhat sane.

After I got home, I checked everything, checked the connections, checked the other SDRs on the same antenna, and all appeared to be okay.
Intermittently, I'll see something like this:
image
The audio stream is disturbed at the same time that the waterfall is disturbed. Temperatures appear to be okay, sitting stable at ~47-48 degrees @1GHz

I haven't noticed the issue showing again today. I'm just noting this odd behaviour here in case anyone else sees similar.

Attachments:
https://forum.kiwisdr.com/uploads/Uploader/0f/d186d29faaa9b5bb2cdd48a816610f.png
https://forum.kiwisdr.com/uploads/Uploader/e9/1440c701fca7594a777a2cba683c60.jpg

Comments

  • jksjks
    Are you using an active antenna? Note how in some places the signal level drops dramatically for a period of time. This is easily seen in the case of signals that are strong carriers (yellow arrows). Also note the appearance of what look very much like the familiar wandering switching power supply RFI during the periods of attenuation (white arrows). So something is seriously wrong here. I would try a simple wire antenna and see how it compares. Just a modest wire elevated from the ground slightly for a short distance. Run it outside across the top of some bushes or something temporarily. It will pickup some signals.

    image

    Attachments:
    https://forum.kiwisdr.com/uploads/Uploader/14/ed661ed71be224e0a06ba46b3934ec.png
  • cathalferriscathalferris
    Hi John, thanks for looking in on that. Much appreciated!

    Yes, it's an active antenna - specifically an active-antenna.eu AAA-1c. I did have some manipulation of the radio-end of the antenna system when I was doing the install/swap of the BBAI, and I may have loosened a wire with the antenna type selection wire block. The quality of my soldering of that section is definitely amateur and needs to be redone once I get the components to replace the current connectors there. There's also the possibility that one of the kitties stepped on things there. The antenna, the kiwi cooling fans, and the Kiwi itself are powered by three separate switchmode power supplies, I haven't yet obtained my linear power supplies. I might put an oscilloscope onto those and see which one looks closest to the patterns as per white arrows above

    Further examination to be done over the weekend when I get back to the apartment I suppose! The issue has not shown since the above screen captures at least.

    I'm in a 6th floor apartment here in Zurich so the ability to use alternate antennas is a bit difficult, and causes quite a lot of RFI from 12MHz and up. I do have a qrpguys.com 40m-10m ununtenna that I'll string across the apartment tomorrow to test. I'll also be doing simultaneous monitoring with an SDRPlus, and a HackRF on another antenna so that will corroborate any antenna-specific shenanigans. This kind of troubleshooting is actually fun..
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