well mr 2N3055, did you read my page ? seen any of the pictures ?
then you would have noted the noise it also seen in 1 2 5 10 and 20mV/Div
I dont need the 500uV div feature, it just came with the all features upgrade,
and the 500uV div feature should of course not affect any other settings.
SO YES, there is something odd spreading noise inside this type of scope,
and you can google a little bit and see it is not only me who see it.
What's with the attitude?
DS1000Z is not low noise scope. It has some clock bleed in signal but many scopes do. It is you who expect too much of a very cheap little fellow that is quite nice little scope.
In attachment you can see that it is well in specs, it's noise floor is in fact lower than 18000 USD Keysight both in P-P and RMS, because keysight has much larger bandwidth. With 20 MHz bandwidth limit on, Keysight has 10 dB lower noise floor and spurs. Although you can clearly see that it also has sampling clock spurs bleed in spectra..
For the money DS1000Z does good job.
If you need lover noise, sell it and buy SDS1000X-E instead..
That is cheapest option that will give lover noise for not too much money..