Read other posts in the "Elephant in the Test Room" series here.Recap on this thread:The room: - MIL-STD RF immunity testing – 1-18GHz 200v/mThe elephant: everyone in the room is aware that a significant fraction of the ‘calibrated’ 200v/m test field is actually created at the wrong test frequency.The culprit: notoriously high ‘start of band’ harmonics produced by all octave … [Read more...]
Apples and Oranges … If Only!
Military use of commercial equipment has grown exponentially over the last decade; and not just in the area of whole equipment, which is easy to see. The use of commercial components and subassemblies within systems has grown as well, so that parts of what look like a full military development effort are actually commercial items. What’s an DoD EMC engineer to do? I wish … [Read more...]
Elephants in the Test Room
Read other posts in the "Elephant in the Test Room" series here. I apologize for the prolonged absence, my attention was drawn elsewhere for a while – back in the saddle now for the foreseeable future at a rate of at least one blog post per month.For this new raft of posts, I decided to highlight open EMC controversies that everyone seems to know about, yet few talk about. I … [Read more...]
Togetherness is Another Way of Saying Well Bonded
Electromagnetic compatibility (EMC) is often described in terms of RF coupling phenomena. Usually the big four: Radiated and Conducted Emission and Radiated and Conducted Susceptibility/Immunity. These four elements cover all of the EMC issues in a very broad sense. Occasionally lightning and ESD will be divorced from susceptibility and described as if these two items were … [Read more...]
And Now, a Shameless Plug….
The Joint Spectrum Center (part of DISA for those of you who support the US DoD) sponsors and populates the premier electromagnetic environmental effects and spectrum supportability web site on the World Wide Web.We in the business know that compliance with Spectrum Supportability (SS) requirements and control of electromagnetic environmental effects (E3) can be critical … [Read more...]
The Ground Loop
Several readers have made comments regarding multipoint grounding (MPG) systems. The concern is that this arrangement creates multiple ground loops. As a result, we need to address that. As some of you know, I make a lot of presentations and teach a lot of EMC seminars. A long, long time ago, I was discussing ground loops in one of my training classes … [Read more...]
Do You Feel Lucky?
Do You Feel Lucky? Well do ya…..PUNK?Classic line from a classic movie, Dirty Harry, who was also in the Enforcer. Frankly I forget which one came first. So who is our enforcer of electromagnetic environmental effects (E3) requirements, specifically for US DoD program? The requirement to field electromagnetically compatible systems is mandated in DoD … [Read more...]
Can an Ordinary Human Stop RF Noise?
When my son was working on his EE degree he found an article titled: Stop That Noise in the IEEE Potentials, October - November 1995. Being a dutiful son, he brought it home to his EMC-dad and I read it. It is a great little article giving an overview of the cause and effect of EMC problems. The articles primary thrust is to introduce EMC to college students and encourage them … [Read more...]
Where are the Resumes?
Sometimes it’s a bit of a struggle to come up with something relevant to write. I try to write about topical subjects in EMC or spectrum supportability, but sometimes things are just slow. Right now we’re trying to hire a RF Spectrum engineers for some Navy work and it's just hard to find quality resumes. I started wondering why, and I’ve concluded it’s a combination of high … [Read more...]
Let’s Twist Again
Some time ago I introduced the equation for DM radiation from a loop. I also let Howard Johnson make fun of the single ended crowd that do not believe in loops by quoting from one of his articles. (Refer to “Why Digital Engineers Don’t Believe in EMC”, IEEE EMC Society Newsletter, Spring 1998.) The whole article is available on the internet.Anyway, to continue:E = … [Read more...]
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