WiFi interference on Siglent oscilloscope

[tony359]

Hi all,

My Powerline adaptor is getting into my oscilloscope like crazy. I can do larger measurements without too much hassle but smaller measurements are flooded by the noise.

Is there a way to stop that from happening?

Using a Network cable to bring the Internet to my garage is possible but a pain in the neck so I would only consider it as a last resort.

Here is a video of it. Also a pic for future reference.

https://share.icloud.com/photos/05frIzPO_88vhTLcRl-x_GAVQ

Thank you!

[DuPe]

"Is there a way to stop that from happening?"

powerline is known for such interferences.
Just use real wireless wifi bridge.

I never had such problems by using them

[tony359]

indeed that was one of the options but it's not straightfoward as the room is insulated with foil and there is very little reception inside. I'll have to install something outside - or under the roof - and something with a decent speed.

Any suggestions?

There's no way to remove those interferences? Any wi-fi extension I've done in the years haven't worked very well though.

[adam4521]

The modern powerline comms use frequencies into MHz, differential mode between L and N, and, I understand, also common mode between that pair and PE. Maybe you could try a powerline filter, like this one:
https://www.dem-uk.com/roxburgh/products/industrial_emc_filters/single_phase_free_standing_iec_in_line_filter_pmf/pmf6.asp
Data sheet shows > 40dB insertion loss at 1MHz+.
RS catalogue ref: 122-9448.
For what it is, quite expensive at £52+VAT... Is there a less expensive way of doing it? 4G hotspot? We should get a few more opinions on here!

[tautech]

indeed that was one of the options but it's not straightforward as the room is insulated with foil and there is very little reception inside.

Why was the foil installed in the first place ?
Is it foil lined sheet lining ?

I'll have to install something outside - or under the roof - and something with a decent speed.
Any suggestions?

Distance needs be known before any product recommendation can be made.


Oh and BTW, does having the trigger set within the amplitude of the waveform make any difference ?

[tony359]

Foil is on the insulation boards!

Well you mentioned WiFi extender and I have a FritzBoz! as my home router. You made me remember that my ISP sent me another one - newer but basically the same box. FritzBox support Mesh network and they only work in Mesh between AVM products.

So I tried it. I installed the new box above the ceiling insulation boards - around 15m from the main router with a brickwall and a window in between. Then routed an Ethernet cable to the main switch in my garage.

Result: the ceiling insulation is not enough to stop the repeated WiFi and the box connects to my router at 5Ghz at 500Mbit/s (actual test show 200Mbit actual throughput via Ethernet). I'd say similar results than before with Powerline - but lower and more consistent ping.

And no more interferences. Only downside, the Siglent doesn't like the new WiFi - I understand it's a known issue with the Siglent but it was ok with the Powerline Wifi... RJ45 it is. (tautech, I see you are a Siglent distributor, any help on this? )

So, thanks. Indeed extending WiFi was my second option but I know that extending WiFi can be sketchy so I went for Powerline instead. But since I got this new Fritzbox for free...

Trigger set to the amplitude? Can you elaborate a bit more?

Adam,

Thanks for searching that for me. Do you think that would have helped considering that an isolation transformer didn't? In the end the oscilloscope is always going to be connected to the DUT - which is connected to mains

[tautech]

Foil is on the insulation boards!

Only downside, the Siglent doesn't like the new WiFi - I understand it's a known issue with the Siglent but it was ok with the Powerline Wifi... RJ45 it is. (tautech, I see you are a Siglent distributor, any help on this? )

If you don't have the latest FW installed do it now !
Your Sys Info should be displaying an OS of 8.2 or 8.3 and FW version 37R9
https://int.siglent.com/upload_file/zip/firmware/Oscilloscope/SDS1xx4X-E_V6.1.37R9_EN.zip

You'll probably also not have a Saved IP in the scope which is best to have if you want/need reliable repeatable WiFi connectivity.

Trigger set to the amplitude? Can you elaborate a bit more?

Watch for the trigger level indicator arrow/pointer to move to a 50% level when you press the level encoder. 
In reality what you see on the display means little unless your trigger level is within the waveform amplitude and triggering is rock solid stable.


There's many here that know these great little scopes well however to get good quality assistance we need good quality questions and preferably with screenshots that you should practice getting to USB and then posting here. Don't forget to have relevant menus displayed for us to see your settings. 

[tony359]

If you don't have the latest FW installed do it now !
Your Sys Info should be displaying an OS of 8.2 or 8.3 and FW version 37R9
https://int.siglent.com/upload_file/zip/firmware/Oscilloscope/SDS1xx4X-E_V6.1.37R9_EN.zip

I am one step behind - I updated not long ago and I didn't realise I would get another version so soon. I am on 8.2/6.1.37R8. I'll update tomorrow thanks!

You'll probably also not have a Saved IP in the scope which is best to have if you want/need reliable repeatable WiFi connectivity.

I don't. It's on DHCP.

Watch for the trigger level indicator arrow/pointer to move to a 50% level when you press the level encoder. 
In reality what you see on the display means little unless your trigger level is within the waveform amplitude and triggering is rock solid stable.

Oh I see what you mean. No, that was a 100Hz sinewave from a signal generator. I didn't trigger it but those noise things were from the Powerline. I think you can see it when no signal is applied in the video. They would also disappear the very moment I switched the Powerline off.

There's many here that know these great little scopes well however to get good quality assistance we need good quality questions and preferably with screenshots that you should practice getting to USB and then posting here. Don't forget to have relevant menus displayed for us to see your settings. 

Hey, I am using the Siglent web interface to make my youtube videos! And I know how to save to USB!   

Thanks for your help, appreciated!

[adam4521]

Do you think that would have helped considering that an isolation transformer didn't?

Yes, isolation transformer had gone through my mind, or a double conversion UPS. But then I thought unless the latter was a very quiet, 'true sine wave' sort of unit, would likely cause more trouble than it solved. It seems the high frequency common mode signal will couple straight through isolation transformers and power electronics, so these likely not enough on their own. I'm not completely confident about the power filter idea -- although if it did successfully squash powerline comms I would put all test gear and DUT downstream from it (extension outlets etc).

It's great that you've found a workaround using kit from your ISP! I'm still interested in what others would do faced with this situation as I can imagine myself being quite annoyed if a neighbour used powerline comms and there was nothing I could do about powerline signal breaking through*!

(edit * I suppose it is not supposed to -- shunted via N-E link at the utility service head, but I'm suspicious that enough of the common mode signal would leak past that).

[tautech]

You'll probably also not have a Saved IP in the scope which is best to have if you want/need reliable repeatable WiFi connectivity.

I don't. It's on DHCP.

Ok then get an IP or enter a new and higher one to avoid any possible clashes should DHCP assign one the same for another device when the scope is OFF.
Then turn DHCP to OFF and Save your IP and make a note of it so you use that same one each time.

Wired LAN is the way to go however WiFi works pretty good if your access points are configured correctly.
We had some issues a while back until I changed Lease times and then later when our ISP changed out their Modem/AP they all disappeared. 

For my now old preproduction SN# 0012 SDS1104X-E I've used the same saved IP for a couple years now.

[tony359]

Adam
Im a curious person too so it would be nice to know indeed. That said I hope I wouldn’t get power like interference if a neighbour installed it - but in a block of flats may be more relevant indeed.

Tau tech
Ah, I thought I read somewhere that DHCP was a better choice for the siglent. To be fair there’s is nothing wrong with dhcp, a well designed device should perfectly work with that.
If the issue is the changing IP, then that does not happen on my network as each device is bind to its own MAC address in my router, that is, it keeps receiving the same IP over time, it never changes.  I like this more than set a fixed ip on each one of my devices. This way I have central control on the ip scheme.

I can still try locking the siglent via it’s own interface but the thing is that it worked fine with the previous wifi adaptor and the same exact configuration 🙂

Shall give it a go though, thanks.

[tony359]

Just a quick follow up, the Mesh network with the spare FritzBoz! works like a charm. The feed is more or less the same speed I had before but ping is much more consistent - mostly 1-2ms. Also, my Devolo Powerline adaptors are now on sale - they're not cheap to buy so I'm going to make some money out of them.

Thanks for giving me that idea!

[radiolistener]

Is there a way to stop that from happening?

you can disable WiFi interface in the router settings. I had similar issue with operational amplifier, when it works near WiFi router (about 1 meter away), I got about 30-40 dB noise floor spikes within 0-150 kHz bandwidth, it happens about once per second or even more often. Disable WiFi interface in the router helps me to fix that issue.

[tony359]

But the thing is that I need the WiFi! That is why I got a Powerline with WiFi AP on it.

That said, I believe I tried with or without, different sockets and nothing ever worked. The socket I installed on purpose close to the DB (I thought it would give me a better signal) was giving so much interference I couldn't listen to the radio.

Years ago I had Powerline (different brand) in my Home Theatre and - despite not really performing much better than standard WiFi - I had the same interferences in my speakers.

So I guess this is lesson learnt. No more Powerline.

[PA0PBZ]

It's not the WiFi signal that is causing the interference on the scope, it's the powerline box. They use all the dirty tricks in the book to get a signal from one box to the other and they should be made illegal 

[tony359]

To be honest, if they could at least provide a decent speed and latency... I plugged them back in to reset them yesterday. Close sockets but via one short extension: 40Mbit/s (that's a 1.2Gbit adaptor kit). My WiFi at that distance can do 800Mbit/s.