With the recent release of MIL-STD-461F, many military equipment suppliers are wondering what changes occurred between revision E and F and how they may be impacted by the change. Steve Ferguson of Washington Labs in Gaithersburg, MD has written an evaluation of these changes. The Test & Measurement World web site article Military Standard Gets a Revision includes a link to Steve’s excellent white paper.
E3
10
Aug 09
Easy Fix for a Common Ambient Emission Problem
When performing emissions tests within a shielded enclosure (a.k.a. screen room), a common cause of test outages is ambient RF signals. The usual (and typically acceptable) practice is to turn off the unit under test (UUT), re-measure the ambient spectrum, then compare the results between the UUT powered and unpowered tests to identify which emissions are contributed by the UUT and which are contributed by the ambient environment. Not only does this cause additional test time, but sometimes the results are not so easy to interpret if both the UUT and the ambient environment have emissions at the same frequencies, particularly if they are near the same amplitude. This is often the case when the UUT exercising equipment is generating the troubling ambient signal. The culprit is not always the local radio or TV station. Continue reading →
26
Jul 09
EMP Threat to America
One service I provide as an Electromagnetic Environmental Effects (EEE or E3) engineer is to help designers of military equipment and systems prevent damage to their equipment caused by Electromagnetic Pulse (EMP) events. While the EMP threat is well-known in the military community, particularly its effects on strategic and battlefield forces, the potential impact on the civilian domestic infrastructure is virtually ignored.
Several years ago the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack, spearheaded by my congressman Roscoe Bartlett (Maryland, 6th District, Republican), issued a report about the devastating effects of a High Altitude Electromagnetic Pulse (HEMP) event on the domestic U.S. population. A rouge state or terrorist organization could detonate a nuclear device over the U.S. and potentially blast us into the Stone Age without killing people or destroying buildings. The EMP Commission’s Critical National Infrastructure Report (or the Executive Report for those interested in an introduction or ‘lighter reading’) is an excellent treatise on this risk to our way of life.
A grass-roots organization called EMPACT America has sprung up to bring together “local citizenry, civic-minded companies, and grassroots activists to help prepare communities in New York and across America to prepare for an EMP attack. Working with local city governments and first responders, EMPACT America provides for coordination, education, and consulting services, helping to create a growing grassroots movement focused on EMP preparedness and recovery.” This is one of many similar groups likely to grow out of our new world disorder.
Stu Benner
E3 Design Engineer
EMConsulting, LLC
20
Jun 09
Welcome to Stu’s EMConsulting Blog
EMConsulting is an electrical engineering consulting firm that specializes in Electromagnetic Compatibility (EMC).
Whether you call it interference, noise, Radio Frequency Interference (RFI), Electromagnetic Compatibility (EMC), Electromagnetic Interference (EMI), Electromagnetic Environmental Effects (EEE, E3, or E3), solving interference problems is not “black magic.” By considering basic laws of physics, EMConsulting can provide effective engineering solutions to prevent or eliminate electrical interference problems in your products.