I said I understood it was a bug, but what real world measurement fails for you, that is my point? It's a nice anecdote; however, if you were really measuring low-level DC or noise in the low mv range, who would be setting the scale to 160V?
Of course, I could be wrong and this is certainly a nuisance, but I've found it's best to use equipment in ways that enhance its performance rather than in ways magnify its weaknesses. That is true for anything.
BTW, I think in single channel mode, the performance of the scope is outstanding, and that is why I think this bug is nuisance, because it certainly need not be this way.
I don't know if you for some reason refuse to read what I wrote or you're making fun of me...
Not making fun, but I still qualify that I could be wrong. That is why I am asking what real world measurement fails for you?
NO milivolts... Read again.. CH1 AND CH2 on 1V/DIV , probe connected only to CH1
NOTHING on CH2, disconnected, no probe connected...
RMS on CH1 2.07V, RMS on CH2 1.9V !!!
With nothing connected to the CH2 BNC.
Um, I'm talking about what you are complaining about, the RMS reading on CH2, which has nothing connected, so you are measuring very low level noise, no? AND, you said: "6. Set CH2 to20V/div.."
You do realize that is 160V full scale, and the spec is +/-3% of 160V, right? Am I wrong? You should be expecting a straight voltage in the range of -4.8V to +4.8V with the scope set up this way. Am I wrong here? Maybe I am just making a fool of myself. I am not an engineer or anything like that.
CH2 with NOTHING connected to it measures cca 80% of whatever you are measuring on CH1 ( not flecking micro-volts, but 80 % of data from CH1.....)
That fails EVERY real world measurement criteria for that channel and particular RMS measurement.....
If I have NOTHING connected to CH2(no probe, BNC is empty), I can't have spillover from CH1 to CH2 of 1.9V RMS... That is 2 DIVs
I thought you set CH2 to 20V/div/ Two divs is 40 volts, right?
But is a serious thing if you need RMS... I can just measure on CH2 and CH3 as a workaround but it is a serous flaw anyways.. And I didn't buy 4CH scope to use it as a 1CH...
I could have gone with 2CH DS2000 series with just a little more money but I needed 4CH for the things I do...
So I want all channels to work normally.. Of course I will make do with it for the time being.. But it should be fixed eventually..
I don't want this to become an argument of a sorts. I'm persistent because you seem not to understand the problem, and despite your good will to help, you are talking about unconnected things..
I just want to untangle misunderstanding..
All the best..
I still totally understand your perspective. Where I am coming from though is understanding the product specs and limitations that the mfg can impose. You are taking an idealistic point of view, and I totally agree it is a shame because this spillover need not be that way. It may be a trivial matter for Rigol to fix it, or it may involve thousands of man-hours. Rigol is in it to make money, and unless the scope is failing its spec, then they are not bound to fix it, no matter how embarrassing.
And once again, to my point about setting up the instrument in the best possible way to achieve an accurate result should not be dismissed. I'm sure you would do that anyway even without this bug.