How to Plan a MIL-STD-461 Test Chamber
Planning the chamber size, absorber selection and test setup for the mandatory EMC tests of military and aerospace equipment.
3 min readAugust 19, 2026
Where Does the Problem Come From?
Transformers, busbars and high-current cables create low-frequency magnetic fields. These fields can make nearby screens flicker and cause errors in sensitive equipment.
Classic shielding that stops radio signals is not enough against these fields.
Solution
Special materials that redirect the magnetic field are applied to walls, floors or ceilings. Material thickness and number of layers depend on the source and strength of the field.
Sometimes shielding the problematic cable route is the more economical solution.
Measure First
The field level is measured before the work and measured again afterwards to report the improvement.
This makes the effect of the investment clearly visible.
Material and Measurement Details
We explained how magnetic shielding materials work in our magnetic shielding with mu-metal article, and how field measurement is done in our magnetic field measurement article.
We covered the difference between health limits and equipment effects in our ICNIRP limits article. For solutions, see our energy sector page.
Frequently Asked Questions
How long does magnetic shielding take?
From a few days to a few weeks depending on area size; office use is usually affected only briefly.
Is improvement guaranteed after shielding?
The target is set by measurement and verified and reported by measurement after installation.
Can the problem be fixed at the transformer?
Sometimes changes at the source, such as cable layout, are more economical than shielding; measurement shows this option too.
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