EEVblog #1188 - $10 DIY EMC Probe using Scope FFT

How good is your existing oscilloscopes FFT function with the $10 DIY EMC H-field probe compared with a dedicated spectrum analyser?
Dave tries the DIY EMC probe with half a dozen different low cost scopes, so it turned into a bit of a practical FFT shootout:
Rigol DS1054Z
Siglent SDS1202X-E
Keysight DSO1204X
Rohde & Schwarz HMO1202
GW-Instek GDS-1104S
Owon XDS3202A
and the higher end Rohde & Schwarz RTB2004

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[Schwuuuuup]

The Video was worth watching for the hint towards the Memory Setting for FFT on my Rigol Scope alone... Can't wait for the SDR one

[PilotPlater]

Thanks for showing off all the different scopes. That was pretty slick, thanks Dave!

[GadgetUK]

Wow, that's fantastic! I would have never thought a scope with FFT could be used that way.

[Rodrickfung]

We had EMI / EMC testing for our homemade BLDC Motor Controller last week. Unfortunately, we failed the test. The result was nasty between 30MHz and 200MHz which is a low frequency band, but clean and beautiful in high frequency band which ranges from 200MHz and 1GHz. We figured out the bundle of noises mostly come from the high power switching nodes as the noise level significantly goes down when I put the ferrite bead at those nodes. I have intention to alternate the configuration in the BLDC board e.g. Gate Resistances, Switching Frequency, The cable's length blar blar blar to see any differences beforehead the second-test and development of the final prototype. It gave me surprise as I found this video useful from EEVblog ! Kinda fascinating to give me a full picture from EMI theory to pre-test stage before in the lab! I literally learnt alot from the video and plan for the internal test now! I've made the order for the coming DIY EMC probes! Although it's limited in near field test, at least, it's pramagtic and afforadable way for me to have a brief understanding to see what's going on and to "predict" the optimal parameters for mitigrating the issues! Thank you for the lecture!

[gwc]

YES, do the software defined radio spectrum analyzer video.

[iamdarkyoshi]

The DS1054Z is honestly doing quite well in this considering its age and price point

[UpcycleElectronics]

I do not need a new scope. I do not need a new scope. I do not need a new scope...


Doesn't work

I still want a new scope.

[lincolnworsham]

What worked for us is to take the EUT to the test house for a "prescan" and then use the near field to debug problems. With the probes i'm just looking for x dB drop to bring the peek under the limit line.

[DanielLopez-upos]

The RTL-SDR radios are really awesome, using "Q branch direct sampling", on some of them allow you to go down to the hundreds of KHz, without needing any sort of extra circuitry, albeit "only" at 3.2 Million Samples per second.

[JackZimmermann]

Whoa! That Rohde & Schwarz RTB oscilloscope. Thinking instead of buying six-piston calliper brakes for my sports car, getting a new R&S scope instead. So if I crash and die, it's partly your fault Dave! ;) Great video, as always!

[strangersound]

That Keysight is a beauty. The gray color scheme is way easier on the eyes than that bromide off white thing that seems to never go away. ;)

Great video, Dave. This was more than the title suggests. Scope use, comparisons, and more. :)

[stevetobias]

I have ordered the necessary parts to make my own analyser like you made in the other video. Am looking forward to playing with it.

[richosthoff]

GREAT SCOTT, I could sure use an oscilloscope!

[kevincozens]

At 8:07 I like how Dave refers to the 200MHz 4 channel scope as a "low end scope". :) Dave should use the amplifiers when he tests the SDR.

[peterellis]

Fab vid as always Dave :)
SDR here we come!! Ive been designing amplifiers lately and I only have a pc based oscope.
I does me for what i need but a spectrum sdr now that would help me massively
Cant wait
Thanks Dave

[rowifi]

Useful concepts, but only useful if you can subsequently take the product to a calibrated chamber, or if you already know what frequencies are above the limits. What can look like bad emission on a near field probe may often not radiate far at all, and vice versa.

[jafinch]

Great presentation! The use of an oscilloscope as a spectrum analyzer is what got me into this test equipment addiction mess. One of my project plans is to see if I can hack the TDS-520 frankenscope into having more options for FFT. I still need to determine if the memory upgrade is really worth is since the sampling rate isn't so hot. Really need to upgrade the sampling rate.

[mohammad-mahditaghipour]

Useful info.Thanks.
Also please do a video on the E-field probe as well.

[RaySan]

When your SDR Dongle (rtl sdr i guess?) arrives, give the software qspectrumanalyzer a bowl

[seanet]

One good thing the scope is great on is low frequency noise if you are having issues even if you have a nice SpecAn handy.
Most cheap to mid range SpecAn and EMI Recievers only go down to 9khz.

If you play in the military space or select parts of the commercial world you may end up with sub 150khz conducted emissions or even radiated emissions in the case of mil-std and def-stan.