There are some spurs / harmonics seen at 60 MHz . They are also visible sometimes at 144 MHz.
What could be the possible reason for the same ?
How to minimise them ?
It could just be externally generated harmonics from noisy electronics, like your screen or power supply.
If it’s internally generated via ADC saturation by a strong signal entering the Kraken, then you should be able to find that strong signal somewhere in the spectrum.
If it’s external, then not much you can do other than turn off those noisy devices. If it’s internal, you could look into filtering out the offending signal, but you need to take care of the phase shift caused by filtering.
I have the same basic issue, and it is caused by my display. I have a display connected to a Raspberry Pi 5, and I also have an Android tablet connected. Both show noise like you have, but when I turn the display off, the noise on the tablet goes away.
This is with the antennas mounted indoors 4-5 feet away from the display. Today or tomorrow I’ll mount everything on a vehicle, and hopefully the metal roof will isolate the antennas enough that they won’t pick up the noise. (With the display on, and the antennas disconnected, there is no noise on the display.)
