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Rigol DHO800 memory depth / bandwidth upgrades and noise level!
Fungus:
--- Quote from: JDW on January 17, 2024, 08:50:37 am ---I don't have a 50Ω terminator, and I am basically trying to replicate what Fungus did because that is established data we can go by.
--- End quote ---
Just don't connect anything to it. Bare BNCs. 50Ω terminator isn't necessary.
I tried covering them with tin foil to prevent radio interference but it made no difference here.
YMMV, it depends where you live and what's around you.
--- Quote from: JDW on January 17, 2024, 08:50:37 am ---No, his work is not a gold standard
--- End quote ---
Gee, thanks...
--- Quote from: JDW on January 17, 2024, 08:50:37 am ---Currently, my scope's "Probe" settings for each channel are set to 10x, and that's because I normally use my Probes mechanically switched to the 10x setting. But we're doing this particular test with "no probe attached" so...
--- End quote ---
The ONLY thing probe 10x setting does is divide all the numbers shown on screen by 10 because the probe has a 10x resistor divider inside it. It makes no changes to the hardware.
The setting should obviously be at 1x to show correct values for this test.
Bud:
--- Quote from: Aldo22 on January 17, 2024, 11:06:49 am ---Have I forgotten something?
--- End quote ---
Yes. A cookie tin box large enough for the scope to fit inside, strapped with a gage 8 wire to the cold water pipe.
JDW:
--- Quote from: Fungus on January 17, 2024, 08:09:46 pm ---The setting should obviously be at 1x to show correct values for this test.
--- End quote ---
Really?? 1x?
As mentioned in the closing sentence of my previous post, I get a "Current" column value of 256uV when the scope is set to 10x. Changing the scope setting for CH1, which is the channel I was testing) to 1x would then show a value of 25.6uV. Your measured values were approximately 200uV. Therefore, I do believe the 10x setting on the scope must be correct unless one wishes to argue that a measured value of 25.6uV is correct, which would then means my scope is significantly lower noise than yours.
Note that in that final test, I had no probes attached. I merely shorted the middle BNC pin to its outer ground via the shortest wire possible.
Bud:
--- Quote from: JDW on January 17, 2024, 10:08:45 pm --- Changing the scope setting for CH1, which is the channel I was testing) to 1x would then show a value of 25.6uV.
--- End quote ---
No "would". Switch and check. You were advised to do the right thing.
JDW:
--- Quote from: Bud on January 17, 2024, 10:14:36 pm ---
--- Quote from: JDW on January 17, 2024, 10:08:45 pm --- Changing the scope setting for CH1, which is the channel I was testing) to 1x would then show a value of 25.6uV.
--- End quote ---
No "would". Switch and check. You were advised to do the right thing.
--- End quote ---
:palm:
Based on your strongly worded remarks above, I suspect that if I had said "When you wet your fingers and then short them across bare wires in your wall socket with active AC power flowing, you would receive a shock" you would have told me: "try it and see."
Here's the video proof you asked for, which again, is only common sense and is but an extension of the same testing I did yesterday...
https://youtu.be/OEXGotlZeiI
For those too lazy to watch the video evidence, the fact is that the numbers shown in the "Current" column are 10x larger when you set your channel to 10x (scope setting) as compared to the numbers in the "Current" column when you set the scope to 1x, for the particular channel being used at the time, which in my case is CH1. This is exactly what I said previously.
Now I hope that settles it.
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