MIL-STD 461

MIL-STD-461

MIL-STD-461 is the US Department of Defense standard defining EMI control requirements for military subsystems and equipment. This article covers its applicability, the major test categories (CE, CS, RE, RS), and Compatible Electronics' military EMC testing services. Part of the Compatible Electronics Learning Center.

What is MIL-STD-461?

MIL-STD-461 is a United States Department of Defense Interface Standard that establishes requirements for the control of electromagnetic interference (EMI) characteristics of subsystems and equipment. It applies to equipment and subsystems intended for military applications — ground, naval, airborne, space, and combinations thereof — and specifies both emission limits (to prevent interference to other systems) and susceptibility limits (to ensure the equipment is immune to its intended operational environment).

The current edition is MIL-STD-461G (2015), though earlier editions (MIL-STD-461E, 461F) are still referenced in many contracts. Compatible Electronics provides MIL-STD-461 military EMC testing services for defense contractors and manufacturers of military equipment.

Major Test Requirements

MIL-STD-461 organizes requirements into four categories — CE (conducted emissions), CS (conducted susceptibility), RE (radiated emissions), and RS (radiated susceptibility) — with individual tests designated by number within each category:

Conducted Emissions

CE101 and CE102 measure conducted emissions on power leads from 30 Hz to 10 MHz and 10 kHz to 10 MHz respectively. CE106 measures conducted emissions on antenna terminals. These tests identify disturbances that would be conducted back onto the platform power supply or radiated via antenna cables.

Conducted Susceptibility

CS tests (CS101, CS114, CS115, CS116, CS117, CS118) inject disturbances onto power leads, signal cables, and antenna terminals to verify the equipment operates correctly in the presence of conducted interference from other equipment on the same platform.

Radiated Emissions

RE101 (magnetic field, 30 Hz–100 kHz) and RE102 (electric field, 2 MHz–18 GHz) measure the electromagnetic fields radiated from the equipment and its associated cables. These limits prevent interference to co-located sensitive receivers.

Radiated Susceptibility

RS101 (magnetic field) and RS103 (electric field, 2 MHz–18 GHz or higher) expose the equipment to defined electromagnetic fields to verify it continues to operate correctly in the presence of strong radiated fields from radar, communications transmitters, and other sources in the military operational environment.

Platform Applicability

MIL-STD-461 applies different requirements based on the platform on which the equipment operates:

Army (Ground): CE102, CE106, CS101, CS114, CS115, CS116, RE102, RS103
Navy (Surface Ship): CE101, CE102, CE106, CS101, CS114, CS115, CS116, RE101, RE102, RS101, RS103
Navy (Submarine): Similar to surface ship with additional requirements
Air Force / Aircraft: CE102, CE106, CS114, CS115, CS116, RE102, RS103
Space: Tailored requirements based on mission profile

Specific applicability is determined by the procuring activity and the platform installation environment. Test engineers review the Statement of Work and applicable contract requirements to determine the exact suite of tests required.