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Old 02-23-2021, 09:15 PM   #41
EasyGoing1
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Default Re: Oscilliscopes

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looked at the vid, not sure the size of those spikes but they are super short - it could be noise from nearby equipment.
I'll be damned ... you know ... I don't think people give you enough credit around here ...

I moved the scope to the next room ... nothing electronic turned on within 30 feet of it and I just now took this video - check it out!
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Old 02-23-2021, 09:19 PM   #42
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Default Re: Oscilliscopes

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looked at the vid, not sure the size of those spikes but they are super short - it could be noise from nearby equipment.
Now if this thing is behaving NORMALLY, I'll leave it alone and keep it, but if you think it might even be slightly defective, I got Amazon Prime ... they'll send me a new one, and come pick this one up at no cost to me with no questions asked.

What would you do?
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Old 02-24-2021, 10:52 AM   #43
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Default Re: Oscilliscopes

well if you think it's a problem, go ask tautech i think he's called, on eevblog.
he's a siglent rep
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Old 02-25-2021, 04:42 AM   #44
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Default Re: Oscilliscopes

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well if you think it's a problem, go ask tautech i think he's called, on eevblog.
he's a siglent rep
This is my first real oscilloscope. I have no idea if they are normally susceptible to RF noise like that. It does seem to me to be a bit much, but, if this is normal for scopes, then I will simply be aware of it and act accordingly moving forward. But if this is not something that is standard with scopes, then I should get it replaced.

My question is, what would YOU do if it were your scope?
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Old 02-25-2021, 05:00 AM   #45
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Default Re: Oscilliscopes

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well if you think it's a problem, go ask tautech i think he's called, on eevblog.
he's a siglent rep
OK, I just created an account on eevblog ... how do I find this "tautech" character?
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Old 02-25-2021, 05:23 AM   #46
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Default Re: Oscilliscopes

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OK, I just created an account on eevblog ... how do I find this "tautech" character?
Click the members tab at the top of the forum page.
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Old 02-25-2021, 10:08 AM   #47
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Default Re: Oscilliscopes

do you get the spikes without any probes?

btw, try to find the cause - it will effect other stuff like radio.
i suspect it's a low current psu - like an led lamp.
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Old 02-25-2021, 12:53 PM   #48
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Default Re: Oscilliscopes

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Originally Posted by EasyGoing1 View Post
Now if this thing is behaving NORMALLY, I'll leave it alone and keep it, but if you think it might even be slightly defective, I got Amazon Prime ... they'll send me a new one, and come pick this one up at no cost to me with no questions asked.

What would you do?
This looks normal to me, but one important thing you did not mention yet:
stj asked if you had removed the ground clip when taking these measurements?
It is important to understand that the ground clip acts like an antenna:
That is why they include that little spring you can use instead of the long ground wire.
I.e. if you are going to perform high frequency measurements you can't use the ground wire!
(And if you are using the scopes built in probe compensation signal then it is not needed anyway since it is anyway already referenced to the scopes (mains) ground).
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Old 03-08-2021, 06:36 PM   #49
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Default Re: Oscilliscopes

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This looks normal to me, but one important thing you did not mention yet:
stj asked if you had removed the ground clip when taking these measurements?
It is important to understand that the ground clip acts like an antenna:
That is why they include that little spring you can use instead of the long ground wire.
I.e. if you are going to perform high frequency measurements you can't use the ground wire!
(And if you are using the scopes built in probe compensation signal then it is not needed anyway since it is anyway already referenced to the scopes (mains) ground).
I had a lengthy conversation with the Siglent rep over on EEVBlogs, and determined that yup it is indeed normal. Also, good to know - if I'm reading what you said correctly - that the ground lead can act as an antenna for nearby noise ... so it's better - in many cases I assume - to simply leave it disconnected when taking a reading?

Also, as I pointed out earlier, the noise goes away completely when I moved the scope to the other room where no nearby electronics were powered on. I haven't tried it yet without the ground lead connected, but I will as soon as I have the opportunity.
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Old 03-08-2021, 06:56 PM   #50
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Default Re: Oscilliscopes

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do you get the spikes without any probes?

btw, try to find the cause - it will effect other stuff like radio.
i suspect it's a low current psu - like an led lamp.
With no probes connected, NO, there is no noise on the screen that I can detect anyway. When I was getting the noise, the scope had right next to it ... just centimeters away, a USB-C port replicator. And it does all kinds of stuff like HDMI on three channels, Gigabit Ethernet, Audio in and out and of course there are lots of digital clocks in that thing and no idea if or how it's shielded or even if it needs to be given how everything it's doing is all digital signaling. No RF of any kind (no Wifi etc.).

Then about half a meter from the scope is my new MacBook Pro. Then about a full meter from the scope is an Xbox One which is technically always on with a low-power kinda thing and a 55" flat screen TV which was also powered off but plugged in. The laptop and the TV would be the only source of RF noise in the WiFi hardware. I have WiFi disabled on the Xbox. Next to the TV which would be about 1.2 meters away from the scope is a Cisco brand Cable TV DVR ... bout 8 years old I would say give or take. It is always on.

OH, also about meter behind the scope is a Logitech - powered subwoofer connected to two speakers. That unit is always on, but I did not have any sound playing through the speakers when I was taking those readings.

But besides those things, there were no powered electronics within 10 meters of the scope.

My guess is that it was the USB-C port replicator.
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Old 03-08-2021, 07:24 PM   #51
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Default Re: Oscilliscopes

the ethernet wouldnt surprise me, it's a low voltage current-drive system.
so it sends short spikes over long wires.

if it is the ethernet then maybe swap that cable for an stp type one.
if it wasnt for the price difference i would use them for everything!
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Old 03-13-2021, 02:23 AM   #52
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Default Re: Oscilliscopes

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Originally Posted by EasyGoing1 View Post
Also, good to know - if I'm reading what you said correctly - that the ground lead can act as an antenna for nearby noise ... so it's better - in many cases I assume - to simply leave it disconnected when taking a reading?
Well you need a ground (or to use two probes instead of the ground).
What I was saying is that the long ground wire acts like a loop antenna:
It is better to use the short spring clip that you can put on the probe tip instead.
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Old 03-22-2021, 01:04 AM   #53
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Default Re: Oscilliscopes

MASTECH is a good brand from China, you can think about it
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Old 03-22-2021, 04:05 AM   #54
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Default Re: Oscilliscopes

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the ethernet wouldnt surprise me, it's a low voltage current-drive system.
so it sends short spikes over long wires.

if it is the ethernet then maybe swap that cable for an stp type one.
if it wasnt for the price difference i would use them for everything!
I had not considered Ethernet either. I always make my own cables ... but a solid stp properly terminated wouldn't be a bad idea ... can't cost that much I wouldn't think for like a 15 meter cable. I was thinking maybe even VLAning the scope would reduce the traffic on that wire but then again ... most TCP/IP stacks in any computer is pretty chatty even without any direct traffic happening ... layer three alone is constantly talking back and forth to anything that will listen.
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Old 03-22-2021, 05:29 AM   #55
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Default Re: Oscilliscopes

hmm...
i cant see why things would be talking unless it's micro$oft upto no good as usual.
maybe some type of service-discovery ping or something.
that or your isp probing your network via TR-069.
which btw is enough reason to NEVER use an isp supplied router/modem!!!
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Old 03-22-2021, 06:23 AM   #56
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Default Re: Oscilliscopes

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hmm...
i cant see why things would be talking unless it's micro$oft upto no good as usual.
maybe some type of service-discovery ping or something.
that or your isp probing your network via TR-069.
which btw is enough reason to NEVER use an isp supplied router/modem!!!
The Macbook uses Bonjour which is multicast.
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Old 03-24-2021, 12:18 PM   #57
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Default Re: Oscilliscopes

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hmm...
i cant see why things would be talking unless it's micro$oft upto no good as usual.
maybe some type of service-discovery ping or something.
that or your isp probing your network via TR-069.
which btw is enough reason to NEVER use an isp supplied router/modem!!!
I use a Netgear router with a custom build of OpenWRT.

And I don't even know what to say on your statement of "i cant see why things would be talking" - I don't even know where to begin but trust me ... your ethernet cables have traffic on them CONSTANTLY! Background code running from just about any web page you happen to have loaded, other network based apps chatting to home base in the background ... layer 3 is routing and routing functions are always checking for hop counts, updating routing tables... the list is endless. I use a program for macs called "Little Snitch" and it sits between your IP stack and your apps and you can literally see EVERYTHING that is chatting about on the network and it's phenomenal what you don't realize is going on without your knowledge. Heck, even the operating systems are constantly chatting it up to various places ...
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Old 03-24-2021, 12:45 PM   #58
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Default Re: Oscilliscopes

the o.s. doesnt surprise me - that's why i use linux.
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Old 03-25-2021, 10:17 PM   #59
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Default Re: Oscilliscopes

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the o.s. doesnt surprise me - that's why i use linux.
The only difference there is that you have more granular control over that behavior, as long as you're custom compiling your kernel...
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