"Steps" in the spectrum every 10 MHz
These are the dBi values of the probe which change every 10MHz.
You can avoid those by using dBm instead of field strength.
But I was already measuring dBm as you can see on the vertical axis.
You also have to remove the antenna calibration setup.
I did not have any calibration settings set.
In this case it is simply the noise level test which is done every 10MHz to give you more dynamic.