Excuse me if my question probably is stupid:
If with a standard stock owon probe there is this problem, there is on the market a "particular probe" that can reduce this problem without use "a short ground" ?
I' am not an expert but the problem is clear for me but I serching for a solution, if exist, a "short ground" is a big compromise is not a "pratical solution".
Other scope don't need "a short ground" becouse the difference is near zero.
I hope exist an alternative ...
If someone have some alternative , pratical solution , (not other informations about the problem that is clear for me), please share
Hello.
I have a SDS8102V and, today I made the "test of noise" using the description of "TomC".
With a 200MHz probe (P6200) I get:
-Peak: Vp=24mV, Vk=9.2mV
-Average: Vp = 14mV, Vk = 7.8mV
With a 100MHz probe (T5100):
-Peak: Vp=19mV, Vk=8.5mV
-Average: Vp=12mV, Vk=6.5mV
I suppose that I don´t have the noise problem. What do you think?
Without probes I have measured a level noise of ~1 mV (BW = 20MHz) [x1] and ~2 mV (Full Band) [x1] with or without 50 ohm load.
I hope that these data be useful.
Best regards.
Hi!
According to your instructions here is the result, with 50ohm terminator on CH1:
Tell the same to all who have problems with noise.
Tell the same to all who have problems with noise.
OWON has improved this oscilloscope at expense of all that have purchased it.
But now, you can think what is Mr Henry. I can tell you... it is not new soft drink brand and it is not new candy. But he do some magic tricks if it meet fast changes...fun guy.
Hi, everybody.
I think so that the fan of my SDS7102 has gone.
I can't hear it (and I don't remember if it is hearing in past) and the front part of oscilloscope is warming!
How can I see, if the fan is working, without open it?
(Sorry, for my english...)
The short answer to your question, at least in my case, I've seen some improvement with a different passive probe while still using a 6" ground wire. This is possible if the probe's input capacitance is lower than the stock Owon's probe. With the stock Owon probe my SD7102 displays 100mV pp of noise in Average 16 acquire mode. The noise generated by my scope is mostly around 100MHz as I have verified with the FFT display. I checked the input capacitance of my probe and the inductance of my 6.5" ground wire with an LC meter and got 15.2 pF and 141nH. The resonance is then around 109MHz which leads me to believe that the noise I see is exaggerated by the Owon stock probe ground wire combination due to its resonant point.
I then tried a Tek P6061 which I had around which has 9.5 pF input capacitance and uses a 6.2" ground wire which measured 125nH. In this case the resonance is around 146MHz and although the ground wire is almost as long as the Owon's the noise displayed by my scope went down to 75mV pp. Note that the P6061 is rated at 60MHz, however, I checked it against the Owon's stock probe and its response up to 110MHz was nearly identical.
I've also tried using a snap on small ferrite core on the Owon's probe stock ground wire. This also causes the noise displayed by my scope to go down to 75mV pp. I calculated the resonant point for this combination and it came out to be around 39MHz. However, this solution will cause exaggeration if you measure signals in that frequency range or if some other device emits common mode noise in that range. I happen to have a laptop PS which emits noise in that range and when I plugged it in the same outlet I was using for the Owon the noise went of the screen.
The best results I've had so far is using a custom made 3" long ground wire with the Owon stock probe or a stock 4.25" ground wire with the P6061. In both cases the noise displayed by my scope goes down to 45mV pp.
What I've learned from all this is that when working with high frequency signals or fast rising signals, the shorter the ground wire the better accuracy you will obtain. In these cases an effort to use the spring ground clip is well justified for me. A long ground wire is tolerable for low frequency work and slow rising signals, and if the Owon's noise is getting in the way because the signals are small, I either use the 20MHz bandwidth limit or the X1 probe setting (6MHz bandwidth limit) depending on the frequencies I'm interested in. If I'm looking at recurring signals I often use the Acquire average mode to get a cleaner more stable display.
What you think about these probes ?
Are better then the standard Owon Probes (and reduce the noise) ?
What are the best of these probes ?
I have forget the other attach.
Except the Owon probes, I have a Hameg HZ-36 Probe with 12/57 capacitance and another germany one (no name) with 11/46 capacitance (1:1/1:10 both).
Neither one has a better behaviour on gnd noise than Owon stock. For my probes, as the capacitance is lower as worst be the gnd noise!
Here are two captures, one of them is "gnd noise" and the other the same time what is appearing the FFT...almost 100MHz.
The test was done by Owon probe.