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How you can protect aircraft electrical systems from EMI

Protection & Prevention Testing & Assessment

Today’s interview is with Dan Schettler, Product Specialist at Micro-Coax. He talks about how to protect aircraft electrical systems from electronic magnetic interference (EMI).

Dan’s company, Micro-Coax, has been in business for over fifty years. They have earned a solid reputation for providing custom technical solutions for wires and cable in challenging environments.

The environment under discussion today is EMI. Readers may not realize that aircraft wire can be subjected to EMI from lightning, solar flares, electrostatic discharge, radar, and even other wires! The innovation that Micro-Coax provides is a product called ARACON. It is light-weight, yet it provides as much protection as the heavier metal shielding products.

During the interview Dan talks about how he structured his career around practical electrical engineering as well as sound business knowledge. He also reflected on the challenges on obtaining the coveted ISO 9001:2000 certification for Micro-Coax.

You can also read the transcript below:

Dan Schettler
Dan Schettler

JohnHow are you today Dan?

DanI’m doing well. Thanks John.

JohnYou know, I do a lot of radio, and when I get a company like yours I also have to spell it out so people can find the website. It’s If you’re trying to find the company. Um, so where are you folks based anyway?

DanWe’re located in Pottstown Pennsylvania, which is outside Philadelphia.

JohnI looked at your website this morning. It’s a very nicely designed website. It’s got really good images, graphics, and ways to find out … In fact, we talk about some of the tools it has available there. I just wanted to start out with the website so when people are, you know, listening to this interview, they can maybe tool on over to, kind of scroll around, see what you have there, and you got a little tool that people can actually use for free, so it’s uh, it’s a real good idea. I like the website, like the company, but before we talk about the company and your business offering here, let’s talk about your background. I uh, looked you up on LinkedIn and you have a pretty strong [inaudible 00:03:24] background. How did you ever wind up with Coax?

DanI ended up with Micro-Coax, um, after, you know, completing a degree in electrical engineering at Washington University in St. Louis, and I co-oped with a company in the D.C. area that did microwave component design, [Wincher 00:03:36] engineering. And while working for them, I earned my Master’s of Electrical Engineering from the John’s Hopkins University and submitted my understanding of microwave propagation, and I was recruited out of my … out of, uh, [Wincher 00:03:54] by Micro-Coax, and they brought me onboard as their connector designer in a period where Micro-Coax was shifting from connectors that they sourced to connectors that they designed themselves. And um, wow, that was 20 years ago. Um, it’s 20 years ago this month. And so um-

JohnLet’s not forget you got another fancy degree along the way there too, an MBA, huh?

DanYeah I did actually, about half way through my tenure here, I uh, found the need for a better understanding of business in general and, you know, I was very much a specialist in electrical engineering, and I will always be an engineer, I frequently tell people. Um, but, pursuing the uh, general knowledge that the MBA gave me, gave me a very big, very great appreciation for, uh, business in general and the different moving parts of business.

JohnYou know, that’s music to my ears. I teach in a graduate school in George Town University and I have students who are from 28 to 32, something like that, and um, there always curious about someone like you. You know, you’re very successful with the undergrad. You’re very successful with the master’s degree, yet, you looked in the mirror and you said, “You know what, that ain’t enough, I have to broaden it out.” I mean, you have technical competency, but you have to broaden out to more business aspects, so I think that’s uh, that’s a great lesson for all our youngsters. The youngsters around 30 years old. You know, they’re married, have two kids, and own a house and I call them youngsters. And really have to figure out you know, they have to look in the mirror and say, “Yeah, I’m technically competent,” but sometimes there’s more to it than just that, isn’t there?

DanYes it is. I mean it’s it’s a great instruction, and you really should endeavor to keep learning, and the old sharpen the saw, um, mantra that you hear people say often, but not necessary always follow.

JohnYeah, that’s uh, that’s really what I like to hear. In fact, I have a brother-in-law with a MSCE and a MBA and quite a bright fellow. Um, let’s switch gears and talk about Micro-Coax, been around for 50 years. I mean, you don’t be around for 50 years without having some kind of success, so tell us about the history of the company.

DanMicro-Coax started as a delay line division of a tubing company, this area, this area of Pennsylvania has many specialty tube manufacturers, um, you know, anything from copper tube to steel tube to specialty metals. A lot of medical industry, a lot of electrical industry, um and we started as a division of what was uniform tubes, and um, we’re now a locally owned, you know, separate company from Uniform Tubes, which actually no longer exists. It actually was spun off and sold by our owner. We’re a privately held company. Our, uh, history as Micro-Coax is uh 50 years, but the company itself was much older than that, and you know, we started as that delay line division, where the original patent holders at [Semi 00:07:01] Region Cable are our founders, and our product lines expanded to include flexible cable or both, you know, I would say commercial cables and high performance microwave cables, and EMI shielding products like [aericon 00:07:14] fiber.

JohnWow, that’s quite a legacy to have to look up to, and if you go to your website, which I’m at right now, you find out that somehow rather you endured a ISO certification. You got a ISO 9002, I mean 9001 in 2000, that’s an achievement in and of itself.

DanIt’s an achievement in itself and we’ve gone through many follow up audits. We’ve had ISO certification through many changes of the spec. Um, many revisions of the specification, as well as AS 9102 certification.

JohnI think what’s important for people who are listening, maybe visiting your website, taking notes is that, who do you trust. You know the old Johnny Carson show, Who Do You Trust? A company like yours has been around a long time, strong reputation in the industry, and oh by the way, reinforces with an ISO certification, that you know, chances are, if a guy with your education and background for Micro-Coax says something, you might want to bet on that horse I would think, huh?

DanOne would hope so. I think that our efforts to provide engineers in the industry with data and test method information, you know, is what sets us apart.

JohnGood. Well now we, um, let’s, we have a good idea of your education background and the company, so it it seems to me, when it comes to aerospace engineering, and wires and testing, it seems like the business problem you solve is uh, EMI issues, am I focused correctly on what the business problem, the product that you solve is?

DanI work in our [Aracon 00:08:46] product line and that is the problem that [Aracon 00:08:49] solves. It is an EMI shielding material. It’s a lightweight conductor, made from Dupont’s Kevlar brand fiber, and we metalize that fiber and produce a conductor that is 75% lighter than copper.

JohnAnd I think, uh, there are engineers that are listening to this, but they’re some people who not that sophisticated to understand that, so EMI is um, Electromagnetic Interference. It can come from a lot of different areas, can’t it?

DanYes it can. I mean, electromagnetic interference, you can look at it as a in two ways, so if we create an EMI shield, and EMI shield protects a component, say a wiring harness in an aircraft, from electromagnetic sources or frequencies that are in the environment, and so the information on the data cables or control cables inside that harness are not effected by the outside sources of energy. Visa versa, the information on the harness’ cables don’t radiate and effect other things inside the system of the aircraft. You don’t want one cable talking to another. Um, which is the an analog of what happens with electromagnetic interference. You can think of it as a conversation in a crowded room. You know if you have a bullhorn, you can have that conversation with that relative ease in the crowded room, but if you’re on other sides of the room trying to talk to each other and there’s a lot of noise in the room, you can’t have a conversation, and that’s what a shielding is trying to prevent you from having that interference.

JohnYou know, that seems so obvious to you, but I keep thinking of, you know, lightening is what I think of, and actually I think of solar flares and kind of the standard high school physics EMI issues and uh, I never thought of the actual wires on the aircraft creating problems with other wires, that’s the whole flip-side of the issue here, isn’t it?

DanYes it is. Any power source can be … It’s not only … Your goal in transmitting a signal is to get as much of the signal to from point A to point B, but there are inevitably losses and some of those losses are radiated, and so the quality of your EMI shield is what determines how much power gets radiated, and we can talk about that in terms of how many deviant shielding does an EMI shield provide.

JohnAnd if uh, I guess you would call it a leak, that could lead to degradation, malfunction, many issues down the road, can’t it?

DanEssentially it leads to loss of information and perhaps corruption of information and you know, if you think about anything, particularly in control signals, you know, the last thing you want is to be, you know, issuing a command to any part of an aircraft and having it do something that you didn’t expect.

JohnI was, uh, watching the news in the last few days, and I saw that Jeff Pissos, he had a rocket that went up in the air and it came back down and it landed or they caught it somehow rather, and I guess … What I was thinking of is the cost of putting a pound in space. It’s really expensive, but the same cost is expensive to put things on an aircraft itself, isn’t it? And so any time you can do controlled weight, that’s an advantage.

DanWe often talk about a cost per pound, um, cost per pound saved, as a metric for what makes sense in light weight options when you’re looking at wire harness design, and you know, you’re correct in saying the space industry has a different metric than the aerospace industry, and there’s a different metric for military aircraft versus commercial aircraft, and as you could imagine, it’s actually a declining metric in space to get a pound into space can cost upwards of tens of thousands of dollars, um, so if you’re … If you’ve got a satellite that’s heavy, um, there’s a lot of resources that you could bring to bear to solve those problems.

If you liked this topic, you may want to read the following Lectromec’s previous articles:

In case you would like to get your wire or cable tested, our list of Wire and Cable Certification Testing can assist you find the test that would best suit your needs.

JohnSo we look in the sky at night, we see some satellites. We see a lot of your products up there. Your name’s on there isn’t it?

DanWe have a lot of product, both … So, Aracon’s used as a braid in harnesses, but it’s also used as a braid in Microwave cables. Um, so our space flight cables include Aracon as a braid instead of copper.

JohnAnd the main value of that, of course, is weight, huh?

DanYes, it takes about 30% of the weight, up to 30% of the weight of the cable out.

JohnSo um, what kind of people do you deal with? Are these mostly aerospace engineers from all over the world who are designing products and then they contact you and go, “Hey Dan, I have a problem with A, B, and C.” Is that a typical customer of yours?

DanTypical customers are folks working in the harnessing, electrical … You know, the electrical wiring interconnect system engineers, EWIS engineers. Um, and you also work with folks that are mass effects engineers, so they’re looking at how do you take weight out of the aircraft, how is the aircraft balanced? Um, the balance of an aircraft, particularly in Rotorcraft, that’s important, so you can see efforts to remove weight in proportion to the aircraft, if it’s tail heavy, say.

JohnMm-hmm (affirmative)-

DanSo, they’re different considerations, but generally they’re all connected to the wiring interconnect side of the aircraft design.

JohnMu guess is it’s not just a design, there are … It’s got to be MRO maintenance groups out there that, uh, take an existing plane and modify it somehow to add wireless, to add services, uh, television screens, uh, and so, my guess is that they might be giving old Dan a call too and saying, “Well gees, we’re modifying this one plane from this to this, how can I save money on weight?” I think that would be a perfect call for you, wouldn’t it?

DanIndeed John, and that’s certainly happening. We work with several different standards committees in efforts to define a basically a global industry standard for lightweight composite conductors and we’re currently working with, you know, members from industry, members from I’d say academic or the scientific community and members of our military to define a military spec that would provide users with a, you know, set of specifications that they can rely on and qualified products.

JohnI don’t want to get too much in the weeds here, but you know, is this what mil standard 461 is all about?

DanIt’s not mil standard 461, but it’d be a mil standard of that caliber if you’re looking at a … Mil Standard 461 is a radi … is a test method for, uh, radiated initiatives. Um, I don’t have the actual title correct there, but close enough.

JohnYeah, so uh, Micro-Coax over the years has established strong reputation for uh uh, from you either got a cable going from point A to point B, uh uh, make sure that it’s protected with the EMI shielding. What um, … We’ve seen a lot of changes in the last few years with aircraft, and we look at the next five to ten years going on, where do you see the industry heading as far as EMI shielding goes and weight and Micro-Coax?

DanUm, I see lightweight solutions becoming more important. I think the consumer demand for more and more electronic content in our aircraft, um, coupled with, you know, the … Right now our fuel prices are pretty wonderful, right, but that’s not going to be forever. Um, and you take those two factors together and the more electronic equipment you put on an aircraft, the more copper you put on an aircraft potentially, and if I can save the weight by substituting a lightweight conductor for that copper, I increase payload, range. You know, I provide fuel savings, you know there are a number of benefits. I see that happening and they’re different technologies out there that are in the couple decades out time frame, you’re looking at things like carbon nano-tubes, but the composite lightweight conductors like Aracon are here now and have a large amount of heritage.

JohnYeah, can bridge the gap until, I guess you call it CNT, comes of age, is that right?


JohnGood good good. You know what, everyone of these podcasts I do, I talk with aerospace engineers and experts like you and at the end, we always ask the up close and personal questions, so Dan what is your favorite aircraft anyway? When you fly home for the holidays or go in vacation, what’s your favorite aircraft?

DanYou know John, I uh, I really enjoy flying. I fly a lot for my job, and uh, the long international flights on triple 7’s are actually my favorite flights, but I don’t think it’s my favorite aircraft.


DanMy favorite my favorite aircraft is not a commercial aircraft. My dad and mom were both pilots, uh, they were sailplane pilots and uh, I flew once in a Schweizer Sailplane, when I was very young, and I actually believe that there’s probably not a better way to fly.

JohnYou’re mom was a sailplane pilot. Now that’s something to be proud about. Wow. (laughs) That’s an unusual skillset, isn’t it?

DanYes it is.

JohnWell, that’s great. Well thank you very much for your time Dan. Um, Dan Schettler is a product specialist at Micro-Coax, and if you would have more information about the company, you can go to In fact, there’s a calculator you have online, isn’t there? We talked about that and I forgot to mention it, the weight savings calculator, is that right?

DanThe weight savings calculator and it’s actually the fastest way to get to it is at our Aracon website, which has it’s own website, which is and it’s a free little calculator there. You click on it and designers can click in what their specific requirements are and find exactly what the weight is.

DanYes, and they’re always welcome to call me and ask more specific questions if they have them.

JohnYeah, that’s great and it’s a great looking page too. I have it pulled up right here. Well great, I’d like to thank Dan, my guest today. I’d like to thank you for listening to the Lectromec podcast. If you would like to learn more about aerospace wiring, please visit our website at We have free white papers, newsletters, videos, 164 blogs, and much more. Well, just about perfect for your first time.

DanYeah, that was easier than I anticipated. I stumbled a couple times, but …

JohnNo, that gives it authenticity.


JohnYou don’t want to sound like guy selling the Roncomatic. Hey, I’m Dan with the Roncomatic, blah blah 42%, no. It’s a nice little conversation that’s a good for a lot of wide rate … The students going to listen and think, “Oh gees, he did all that and he’s still an MBA in spite of all, wow, so that’s really good.” And I wanted to close with a callback and going to your website ara. you know, so they could figure out how to get that calculator. That’s a nice little call to action, kind of slip that in at the end.


JohnSo, uh, I thought it was real good.

DanOkay, thank you. I appreciate you taking the time.

JohnYeah so-

DanActually, I had to go look up … I had to go find that sailplane. I had to go find it. I couldn’t remember the name, but I could remember what it looked like.

JohnOh, your mom must have been quite an adventurous young lady there, years ago, a wild one I’d say.

DanYeah, my um, this is back in the … this must have been back in the 60s. They were founding members of the glider club outside of-


Dan-outside of Fincastle Virginia, so it was all ridge-line.

JohnWow, they were really gutsy. Gees, is your mom still alive?

DanNo. She passed away a long time ago, but …

JohnSounds like she died in a bar fight, yeah she’s … (laughs). Wow, that’s really something. That’s a great story and and it inspired you to go in the whole aerospace industry I guess. I don’t know.

DanIt certainly … It certainly played a role. I’m uh, I’m certain that my exposure to airplanes, my fascination with things that fly … because I’ve also been in hot air balloons and so … My uncle’s a hot air balloon pilot.

JohnWow, yeah. I remember one time in Oklahoma, we saw a whole … It’s very picturesque when you get a whole group and you get out in the middle of planes. It’s really incredible.

DanThey’re pretty fantastic.


DanI mean, the only thing that’s not fantastic, that was in St. Louis that I did that, and that was um …

JohnKind of midwesty. Yeah, kind of open.

DanMidwesty, you know, you got a lot of places you can land, which is always helpful, though from my uncle’s experience, don’t land in a one year old seedlings … one year old seedlings of asparagus. Don’t do that.

JohnIt’ll be mushy.

DanThe farmer comes out with a shotgun. (laughs)

JohnCost him some money.

DanOh yes, but you know, I worked, when I was … I helped him put balloons up for advertising, uh … You remember when they used to be the Checker Dome in St. Louis?


DanI’ve worked in that parking lot in an August where it was so hot, we had the balloons so hot that a gust came along and lifted the front end of the jeep off the ground.

JohnYeah, I’ve driven through there in the summer.

DanThere’s a lot of lift in that balloon, and there’s a lot of heat. If you have to get it real hot, it get’s squirelly.

JohnYeah. Remember there’s like … I remember grapes growing around that area too. It’s an interesting part of the country there, that whole Missouri area there. It’s kinda of northern but southern but hot but cold, it’s beat up on all sides.

DanYeah, when you go out to the Ozarks, that’s where you find the grapes.

JohnYep, that’s must be … I don’t know why I think about that, but that’s I think about that area that time of year in lat August, that’s when they pop in and people see them on the side of the road. Well Dan, what we’re going to do is we’re send this off to get a transcript of this. We’re going to get it printed into a blog post and put your picture up there and get it out and hopefully get some sales from this, it’ll be great.

DanJohn, thanks a lot.

JohnThanks a lot and I will click this little off button here and I’ll hang up and I guess you can change little uh, if you get to change your icon or something.

DanI have to figure out how I change that Skype ID. It’s not obvious to me how I signed up for it with my email address not intending to.


DanSo we’ll figure that out.


DanIt has something to do with the fact that this is linked to my Microsoft account that I didn’t even know I had.

JohnThat’s strange because I saw there were two Dans that came up and uh, you may have two accounts or something, take a look at that.

DanActually, the other one might be my uncle.


DanHe has the exact same name.

JohnAh that’s good. Okay, well thank you very much and we’ll show you the links to the blog when it’s done.

DanAll right.

JohnBye Dan.

DanYeah, bye bye.