EEVblog #548 - EMC Pre-Compliance Conducted Emissions Testing

[mfeinstein]

Dave I always wondered how all this new DIY projects can hit the american market without a FCC EMC compliance test...how do they dont get fined or sued?

[DL8RI]

Hi,

here are some pictures of my LISN:



Schwarzbeck is a very well-known Company in the EMI/Antenna-Business.

The two big Ls for decoupling the Mains-Line from the EUT are the most dominating Part in this thing. There's another Filter in this shielded part, but it's quite hard to open it, so there's just a "peek-shot".

AFAIK this Unit is not compatible with the standards anymore, but it's nice for me to be able to measure Common- and Differential-Mode noise, since I'm not doing any compliance-stuff in my free-time. I use it to measure and minimize noise on the Line:


In this example I modified a switching-PSU for minimal EMI because it is used in HAM-Radio environment. It was compatible with the standards (commercial PSU), but we wanted more And, yes, i know this setup has nothing to do with any standard in EMC, it was just for orientation.

The Receiver used is a full compliance Receiver from Rohde & Schwarz, the ESHS 30. A bit older (and slow) but still quite good. And of course the must-have 10dB-Attenuator at the Input

[fpliuzzi]

Thanks for the photos Martin. In the near future I plan to construct a simple LISN for my personal use. I found a few different circuits, but I'll probably make something similar to the circuit that I have included below. A couple of the designs that I found use a pair of 50uH coils and a pair of 250uH coils. Your photo of the concentric coils in your unit will be helpful there.

The article I have shows how to make the high current 50uH coils. I just need to purchase the proper y2 type capacitors to help keep the whole thing safe.

I'll have to add some switching so I too can measure Common- and Differential-Mode noise with the simple LISN circuit below. Thanks for mentioning this handy feature on your LISN

Regards,
Frank

[EEVblog]

Dave I always wondered how all this new DIY projects can hit the american market without a FCC EMC compliance test...how do they dont get fined or sued?

Because "everyone does it" is the basic answer, and it's also effectively a self compliance issue. It is not a big deal, and the authority does not know unless someone goes and complains.
And also, kits have been exempt for a long time, although that has varied from country to country.

[mfeinstein]

How much in average does this tests costs and how much time does it takes to get a certification? Just figuring the real impact for regular people like me with DIY projects...

[mfeinstein]

Dave,

Sorry this is not related but I dont see why open a new thread for something as silly as this, but out of curiosity, what happened with your Gossen Metrawatt? I remember you loved it and used it all the time in the early videos but now I just see your Fluke...any disappointments?

[EEVblog]

Sorry this is not related but I dont see why open a new thread for something as silly as this, but out of curiosity, what happened with your Gossen Metrawatt? I remember you loved it and used it all the time in the early videos but now I just see your Fluke...any disappointments?

Yes, the Gossen Energy calibration got wiped in a firmware upgrade that they sent me and advised, and they didn't seem to care too much. Wasn't impressed.
But really, I've got 2 Fluke's and an Agilent on the bench already which is more than enough, so it's just a matter of what's to hand that gets used in the videos. It's not like I'm deliberately avoiding Gossen because of the incident.

[DL8RI]

Hi,

In the near future I plan to construct a simple LISN for my personal use.

maybe this Link is helpful:
http://schwarzbeck.de/Datenblatt/m8127.pdf

The tricky part is to tweak the thing into the values the Standards demand.

[resistor]

Hi Dave,

I just wanted to throw out that I really enjoyed this video, as well as all of your DFM videos.  While it's not as glitzy as some of the others, this is the kind of information that's incredibly valuable to hobbyists like me who aspire to do things the right way, rather than just sticking an Arduino in it and calling it done.  I think it's really important to get this kind of information out that so people can learn how to take the next step from wiring up an MCU prototype to building something real and marketable.

Thanks!

[EEVblog]

I just wanted to throw out that I really enjoyed this video, as well as all of your DFM videos.  While it's not as glitzy as some of the others, this is the kind of information that's incredibly valuable to hobbyists like me who aspire to do things the right way, rather than just sticking an Arduino in it and calling it done.  I think it's really important to get this kind of information out that so people can learn how to take the next step from wiring up an MCU prototype to building something real and marketable.

Thanks, I like to think they are valuable too. Valuable and mainstream popular don't always go together, and that's to be expected.

[DL8RI]

That's not suprising as EMC in general is a very complex field and needs quite a bit pf work to get "into" it.

[mfeinstein]

Dave I think many people will be interested in a series of videos about EMC Compliance, how to run pre-compliance tests, low cost equipment and etc... there isn't many information out there for hobbist and most universities also don't cover the subject. Thanks in advance

[Spikee]

Dave I think many people will be interested in a series of videos about EMC Compliance, how to run pre-compliance tests, low cost equipment and etc... there isn't many information out there for hobbist and most universities also don't cover the subject. Thanks in advance

+1

[resistor]

Dave I think many people will be interested in a series of videos about EMC Compliance, how to run pre-compliance tests, low cost equipment and etc... there isn't many information out there for hobbist and most universities also don't cover the subject. Thanks in advance

+1

+2.  I think Design for Conformance (DFC?) could make a good set of videos.  Maybe a couple on design tips, and a couple of self-testing.

[EEVblog]

Dave I think many people will be interested in a series of videos about EMC Compliance, how to run pre-compliance tests, low cost equipment and etc... there isn't many information out there for hobbist and most universities also don't cover the subject. Thanks in advance

Didn't I just do one on that?   

[mfeinstein]

Yes you did two as far as I can remember...one on conducted emissions (the latest one, in which you point out there is a lot more in the subject), and one showing a huge place in Australia that does the testings, with a room big enough to fit a truck! Still, there is a lot to cover...radiated and pick-up emissions, shielding (which can be very very tricky depending on the frequency range), ESD and so on...

the "EMC Series" (feel free to change the name) could have it's own playlist...just my 2 cents  

[Eclipze]

I would also like to see more on the EMC topic.  I recently did a 1 day course on EMC techniques.  While some of the material was quite useful, there was absolutely no content with respect to testing/identification and measurement.  Quite interested in seeing more on pre-compliance testing, equipment and tricks :-)

[SeanB]

I got an older one that I need to first strip and check before powering it on. Darn heavy beast it is as well.

Wich one? ESH2? ESV?
Or one from another Company?

SDMU 249.3011.53 with a SMDU 242.2010.54

[DL8RI]

Hi,

the SMDU (with the Z1/Z2) is not a Test-Receiver for EMC, but a old (and technically superb) RF-Test-Set.
Here are the manuals down-loadable from a HAM's homepage: http://www.ko4bb.com/manuals/index.php?dir=Rohde_Schwarz/Rohde_Schwarz_SMDU_SignalGenerator

The generator inside the SMDU is a quite unique disciplined but free-running Oszillator inside this drum-shaped scale. Mechanically highly complex.

This thing may be old and heavy but (for example) in terms of side-band-niose it's still very good, especially compared to this Synthi/DDS-Stuff.

[SeanB]

Thanks, there goes my December and January then.

[HighVoltage]

I really liked this video and learned some basics.
Thanks for making this and show us some EMI testin.