I do want to clarify that the spurs are only gone when I place a bar of ferrite material (insulated) across the board.
Today’s experiment was to completely remove the board from the metal enclosure and observe behavior. Any moving any ferrous object within about 15cm of the board causes fluctuations in the noise floor.
So, the next step I’ve taken is to see if there is anything measurable coming from the board…perhaps an oscillation. Well, I didn’t find that, but I did measure this with an AirSpy at a distance of about 20 cm.
If I depress the reset button on the LimeSDR and/or remove power, the broadband noise disappears leaving only some spurs from the AirSpy unit. This is evident in the darker blue band toward the bottom of the waterfall.
This was also observed, when setting the antenna connector to “None” within SDR Console. (This is independent of tuned frequency.)
Some sort of broadbanded floater signals.
To me, it would seem as there is some sort of problem with this particular board. Has anyone else reported such issues?
Joe