Welcome to our new Website!

After three years of admirable service, I decided that it was high time to update the Southwest EMI Consulting website.    I wanted to learn how to create a site in WordPress – just so I could maybe become a little smarter! 

So after some internet-searching, I found a resource that I recommend to anyone interested in setting up their own WordPress site. 

Tyler Moore is a website developer in California, and it turns out that he has quite the presence on YouTube. Since I do better with videos as opposed to boring step by step written instructions, this was ideal.   Not to mention he defines his tutorials as being for those that really don’t have website building experience.  Perfect! 

So i buckled down and ran though his tutorial, step by step. You are looking at the result. 

If you are interested in how he does it, take a look at the video below. 


Or if you like, you can try Tyler’s website here: 

I was really impressed how powerful yet simple the process was.   Tyler, if you ever see this, thanks!!

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WHGB? Where has Glen been? Since EMI is mostly about acronyms I thought I would start with one.
The answer is that I have been taking care of my 88 year old Dad. Last April, he fell and broke his hip and wrist. After a several week hospital stay and months of physical therapy, I’m happy to report that he is doing extremely well. According to him, he had a PCS (Permanent Change of Station) to a Senior Center near us. We had an estate sale and put his house in Sierra Vista on the market (that’s 200 miles away from Mesa). I have to say it’s nice to have him close to us! He just loves his new place. We take walks through a local mall a few times a week and visit with him every Sunday afternoon.
Now that he’s doing so much better, I’m back in the swing of operating Southwest EMI. Fortunately I have great and understanding customers!
Thanks to all who have expressed their well wishes!
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2015 Aerospace Testing Seminar –

Presented my paper on “Evaluating Receiver EMC Safety Margins Using the Through-Antenna Radiated Emissions Test Method” at the Aerospace Testing Seminar in LA last week.

Thanks to my friend Mike Todd from Orbital ATK for taking my photo!

Giving my presentation at the ATS seminar.  It doesn’t look like it, but there were almost 150 attendees in the meeting room! 
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What I learned at the 2015 IEEE EMC Symposium – How High Power Electromagnetic Effects Can Change Our Lives! 

I had the pleasure of attending the 2015 IEEE EMC Symposium in Santa Clara last week.  I have to say that it was one of the better symposia I have been to – loaded with thought-provoking and informative speakers.  But the keynote speech was especially interesting.
It was so interesting, that I thought I would blog about it!

The keynote speech was delivered by Dr. Thomas H. Lee of Stanford University.   Dr. Lee’s style is very down to earth, with amusing engineering ‘sayings’ and remarks.   Even so, he chose a very serious subject to speak about – the vulnerability of our digital world to high power electromagnetic effects. .

Dr. Lee explained that our planet now contains as many cell phones as humans.   Amusingly, he also mentioned that there are 10 times the number of transistors made each year than ants on Earth! (yes, ants. – others have estimated even higher).  We all know that our economy and in many ways our lives are dependent on the internet, and we are becoming more and more connected every year.
But history has shown that we may be vulnerable!

Coronal mass ejections (CMEs), or massive bursts of gas and magnetic fields from our Sun, have been observed as far back as 1859. That CME – also known as the Carrington event – induced one of the largest geomagnetic storms on record.  Aurora could be seen as far south as Hawaii!  Telegraph systems all over Europe and North America failed, and even gave telegraph operators electric shocks. (Ouch!)  Telegraphs operators could continue to receive and send messages despite having disconnected their power supplies.
Another strong CME was detected in 1989. It caused a transformer failure on one of the main power transmission lines in Quebec.   Six million people lost power for nine hours or more. It cost Quebec $2 billion to repair and upgrade their system! 
In 2012, a Carrington-Level Event barely missed Earth.


Dr. Lee also spoke about the July 9, 1962 “Starfish Prime” high altitude nuclear test near Johnson island in the Pacific. It was a ~1.5MT detonation at an altitude of about 250 miles.   This test caused an Electromagnetic Pulse (EMP) that was far larger than expected, and drove monitoring instrumentation off the scale. The EMP knocked out about 300 streetlights, set off numerous burglar alarms, and damaged a microwave link 900 miles away in Hawaii!  Many folks in Hawaii were able to see the blast, possibly because the event was advertised in the newspaper!  Since it was high-altitude, the blast also formed radiation belts around the earth.  These man-made radiation belts eventually crippled 1/3 of all low earth orbit (LEO) satellites that were in orbit at the time.

Needless to say, CME and EMP events could have a devastating effect on our connected society. In addition to the internet and cellular infrastructure, the ever expanding Smart Grid and the machine to machine connectivity of the Internet of Things are all potentially vulnerable.
As EMI engineers we are on the front line.
Many of us EMI engineers have designed circuits to be lightning or EMP resistant.  Fortunately, there’s a technical committee (TC) within the IEEE EMC Society that specializes in High Power Electromagnetics. (TC5 – Chaired by Dr. William Radasky).   Because of Dr. Lee’s interesting speech, I made time to sit in on the TC5 meeting. 
TC5 is not only concerned with CME’s and EMP but is also the IEEE’s technical committee concerned with other high power phenomena, such as Lightning, Intentional EMI (IEMI) and Electrostatic Discharge.
I learned that there are six working groups presently in process of looking into existing lightning standards.   There has been work by the power systems council Cigre stating that levels in present lightning standards may be as much as 10x too low!   That includes our technical standards for commercial aircraft!!
I also learned that Intentional EMI (IEMI) is a ‘hot topic’. For those of you not familiar with it, it’s defined as “Intentional malicious generation of electromagnetic energy introducing noise or signals into electric and electronic systems, thus disrupting, confusing or damaging these systems for terrorist or criminal purposes”.  That’s right, the bad guys are using EMI against us! 
There were 6 presentations about IEMI at this 2015 symposium, all of which were well attended by more than 40 people.  Dr. Radasky spoke of one case where a security video camera was intentionally interfered with by criminals.  When radiated, the image froze – which if you think about it, that’s the worst thing that could happen.   One of the outcomes of TC5 was the publication of IEEE 1642, the “Recommended Practice for Protecting Publicly Accessible Computer Systems from Intentional Electromagnetic Interference (IEMI).

My impression is that’s it’s a good thing we have such a great deal of interest and activity on issues that could affect our very lives!   It’s a great time to be an EMI engineer!
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What to do just before you go for EMI testing….

The Pre-Test Setup – often forgotten but so important!

In many cases, companies don’t have an in-house EMI test lab and have to travel for hours to find an open lab that meets their needs.  Some larger companies have in-house labs, but they are often swamped and may be difficult to schedule.  At the end of the day, lab time is costly and it’s important that you make your time in the EMI lab count!   

After months of design, assembly and integration, deadlines approach. Your ‘green-light’ product development schedule is a distant memory and as an engineer, it’s all you can do to get the hardware working, schedule a lab, and ….go!

But…. STOP!  As an EMI lab manger I’ve seen it all too often – Incredible as it may seem, electronic systems are often fully integrated for the first time when they are set up for EMI!  Sometimes days are wasted unboxing hardware, trying to install cables and connectors, and getting the system working while in the lab. And sometimes, it doesn’t go well. 

Set it up before you go! 

Before leaving for the lab, remove your entire system from the engineering development bench and set it up as you would in an EMI lab. 

One company I worked for had an unused EMI test chamber that was mostly used for storage when I arrived. That was an opportunity for me to establish a pre-test setup process, which saved countless headaches when I ultimately reached the outside lab.  Here are some of the highlights:

Place your hardware on a test bench – just as if it was in a lab. 

For MIL-STD and Aerospace EMI tests, that usually means a conductive bench.   That may be the first time that all hardware is ‘tied-together’ to a common ground.  This not only helps resolving issues like unforeseen ground loops, but will give you an opportunity to check your hardware bonding. Remember that MIL-STD and Aerospace EMI tests usually require bonding to the conductive bench to simulate the actual application, so if there are special fixtures needed to bond your hardware to a vehicle frame, now’s the time to use them and try them out.  This is the time to get out that 4-probe ‘Bonding’ milliOhm meter to make sure that the hardware meets the bonding requirements.   Measure from each box to the conductive surface, then across each critical interface. This will keep you from being surprised by an errant paint job or missing/ill-fitting hardware. Commercial companies will want to set up the equipment on an equipment cart similar in size to one provided by the lab.  (Find and …) Install all peripherals and loopback connectors, making sure there’s room on the cart. 

Connect each test cable as it will be connected in the lab. 

Again, MIL-STD and Aerospace companies will want to check connector to box and cable shield to connector bonding. Know the lab’s bench size and layout, and make sure that the cables can be run along the front of the bench as required in the test procedure.  Commercial companies will want to connect all interface cables leading to peripherals or loopbacks. Don’t guess that the lab will have a particular cable – even if it’s common.  It’s good to bring all cables with you! 

Simulate each interface cable’s path through the chamber wall.  

For MIL-STD and Aerospace tests, I always recommend using filter pin connectors or fully shielded cables when penetrating a chamber wall.   Use both if you can get away with it.   To make the transition to a lab easier, it’s best to establish a ‘standard’ cable penetration panel and use it in your pre-test setup. Ground the cable shields (usually through the penetration panel) to the common bench top ground, providing a path for the shunt capacitors in the filter connectors.  It’s better to know that an interface will have issues with shunt capacitance before you set up for the final test! 

LISN’s/LSC’s/ISN’s etc… 

Be aware that power inputs will be attached to Line Impedance Stabilization Networks (or LISN’s) when under test. I was lucky when I inherited the unused lab – it had a nice set of LISN’s already in it. Put them in place in your power lines to make sure that your system will power up properly. 

A Caution to Space Companies:  
You probably already know that flying heavy series inductors isn’t very cost effective from a launch standpoint.  A LISN can have 50uH of series inductance. Installing a 50 uH LISN in series with each power lead can destabilize a switching power supply – and can lead to disastrous results! Be sure your power system can handle the LISN inductance before you power on. 

Power up and operate your system – after it’s set up.  

Software and functional testing are often the biggest problem when you first arrive at the lab, and finding problems before you go is often the biggest potential time saver!  Go through the functional test just like it’s planned in the test procedure.  I have all too often heard the words that “it was supposed to operate that way….” right after the equipment was powered on. Don’t guess – try it.  Remember that some EMI scans can take a long time.  Take equipment heating and duty cycles into consideration.  Also, EMI tests will want to have everything running at the same time, with fast cycle times.  This reduces susceptibility/immunity cycle times and allows for better observation of emissions.  Hopefully, properly designed EMI test software has been created by this time in the design cycle! In any case, run the box before you go!

Pack it and Ship it! 

I’ve seen companies with very complex setups install their equipment on a test bench in their development labs – and then ship the entire bench (including EUT, Cables & all) to the lab!  What a great idea! 

So unless you’re that company, take good photos, label everything, carefully place all your equipment in boxes and ship.   The same folks that were a part of the pretest setup should be at the lab when the equipment arrives! 

One advantage I had when using this approach is that I used the old EMI chamber (and its bench) to ‘store’ the test cables, loads and other miscellaneous bits and pieces when I received them.  I was able to slowly build up the test setup until the day the high value hardware arrived.  

Take it from someone that’s seen it. If you do nothing else, do this. 

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Thinking about an EMI precompliance lab?

Maybe it’s the economy or just random chance, but it seems like many of the companies I’ve talked to recently are looking at creating some sort of in-house precompliance test capability.   It’s a good idea to save precious time and money before testing ‘for score’ at an outside lab and it certainly makes sense for companies who have to go far and wide to find an independent lab to run their tests.
Many folks tell ‘horror’ stories of company’s having to stay at an outside lab for weeks, just trying to troubleshoot failures!  Often, these labs are out of town and have limited schedule openings.  But what sort of pre-compliance capability should a company buy?  

Pick the right tests 

 It can safely be said that most EMI problems are found during radiated emissions (RE) testing.   That’s usually true for both commercial (FCC/CE and MIL-STD/Aerospace testing).   But that’s not always the case – and it’s not necessarily the only test that should be a focus for precompliance.
For instance, high-rel equipment that needs ‘five-nines’operating reliability can’t be bothered by transients like EFT or ESD. (See methods EN61000-4-4 and EN61000-4-2).   ESD is especially insidious, since it is often ‘blamed’ for several transient susceptibilities without real data to support the claims.  A simple ESD gun and bench can be a cost effective way to verify your designs.
Also, having the equipment to perform power line conducted emissions is often only a few dollars more than a radiated emissions setup – and can really help your power supply designers feel better about the product before it goes out for formal test.
Look at your company’s test results from the last several design cycles.   Make a judgment of which methods cause the most troubleshooting times.   RE is usually picked as a minimum for a precompliance lab, since solving the RE problem can often systemically resolve other failures – but don’t limit yourself to it!

Set a Budget 

 As a former department manager, I have been on the other side of the fence, where super smart engineers came to me asking for the company’s (limited!) resources.  Your managers are going to expect a positive return on investment (ROI) – and you need to make a super clear argument so they can pitch it to the top brass come budget-setting season.  Here are a few tips:
  • This one’s kind of obvious: Count up the total days spent at an outside lab troubleshooting a problem. Multiply that by the per day lab rate.  If your outside lab charges $2500/day and you spent 10 days troubleshooting at that lab last year, there’s $25,000 of your company’s precious dollars going out the window. Add any per diem employees may have charged.  Generally, a company will want to recoup in internal CAPEX expenditure in 5 years. That’s going to give you a VERY SOUND argument for spending at least $2500 x 5 or $12,500. Scale up or down as appropriate – and be sure to take new product design projections into account.  If the company wants to expand into a new market and generate 5x the design since last year, that’s a good multiplier.
  •  Far less obvious but more important are opportunity costs and the development of intellectual property. Time to market and meeting schedule are often paramount. I knew a company that had a design slogan:  ‘build a little – test a little’.  It really worked.  Having an internal capability of verifying designs that may be reused among many different products/programs at an engineering level reaps huge rewards.   It increases the company IP. At the end of the day, having solid EMI design guidance can spell the difference in the marketplace.  If a company looks at EMI and one of those ‘black magic tests’ that has to be ‘suffered through’ instead of being proactive, it prognosticates its own failure.
  •  Compare EMI to other environments – I still have a hard time comprehending how much many companies focus on Thermal, Vibe, HALT/HASS or other environments, yet are reluctant to spend any capital on EMI.  Often upper management looks at EMI as a single test and asks the question: How much does an EMI lab cost?  I’m here to tell you that I’ve spent over a million dollars on an in-house well-equipped EMI lab.   Twice.   BUT, as we are going to explore in the future, it’s not nearly as costly to develop a precompliance setup that’s targeted to the right tests – for much less than the fleet of $100k/ea thermal chambers that seem to line many engineering labs.

Equipment Selection

In future posts, we’ll examine the kind of equipment you should buy. Do you buy new or used? What may you already have in your inventory? Spectrum analyzers/receivers, antennas, test chambers, troubleshooting equipment – are all part of the equation.   Stay tuned for much more on this subject… 




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