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About Military EMC testing at MET Laboratories

MET Laboratories approaches each Military EMC test ‘Scientifically’ to insure accurate and consistent test results are obtained. Accurate and repeatable test data is imbedded as the root of our business. Obtaining scientific test data requires extensive knowledge, well-written procedures, state-of-the-art test equipment, and post documentation formation.

The least common denominator with all successful Electromagnetic Compliance testing is the people! Test Laboratories must have people with integrity, whom are experienced and interested in obtaining repeatable test data for our clients. Here at MET Laboratories, the EMC Lab integrates years of combined experience, education, and integrity for the test discipline they are assigned. Ultimately, this means that our client’s get what they pay for, the first time, time and time again!

MET Laboratories employs degreed Electrical Engineers, Mechanical Engineers, Chemists, PhD’s, Electronic Technicians, Documentation Specialists, and Project Coordinators to guide our client’s product through each testing phase of their product- from beginning to end.

In addition to skilled personnel, ‘State-of-the-Art’ test equipment is a necessity to operate ahead of technology advancement. Every Test Engineer at MET Laboratories utilizes the latest in advanced test equipment with equipment such as: RF Shielded enclosures, Digital Phosphorus Oscilloscopes, Radio Frequency (RF) Signal Generators, High Power RF amplifiers (200V/m), Rhode & Swartz and Agilent PSA Series Spectrum Analyzers, Transient Generators, Power Generators, Test Antenna Systems, and Environmental Simulation Test Equipment.

At MET Laboratories, the Military EMC Laboratory maintains a plethora of military test specifications used to qualify your electromagnetic product signature for end-user procurement/contractual requirements. In fact, the MIL-STD-461 is often a popular request from our various military customers. Additionally, the MIL EMC Lab at MET Laboratories is able to test to other military EMC Test Specifications including: MIL-STD-704 3 phase Aircraft Power Testing, MIL-STD-1275 Military Vehicle product testing, MIL-STD-1399 Section 300 Shipboard Systems Power testing, RTCA/DO-160 Commercial Aircraft Product testing, and MIL-STD-1399 Section 070 Shipboard DC Magnetic Field testing. Some other type of MIL-STD EMC testing includes MIL-PRF-28800, Shielding Effectiveness according to IEEE-299, MIL-PRF-85045 Fiber Optic Cabling Shielding Effectiveness, MIL-PRF-28876 Fiber Optic Connector Assembly Shielding Effectiveness, and also ASTM E 1851 Durable Rigid Wall Structure Shielding Effectiveness testing.

Being that the majority of MET Laboratories Military EMC customers sell their products to the Government, the Procuring Activity (end-user), often times, require detailed written documentation to support contractual requirements between the ‘Seller’ and the ‘Buyer’. Right from the DI-EMCS-802xx Data Item Description (DID) document, it prescribes the Test Plan/Report requirement for the test data, the format, and all information necessary to document compliance of a component, system, or subsystem within it’s electromagnetic interference (EMI) test requirement. The following outlines the DID documentation requirement for Test Labs to adhere to:

DID EMI Test Plan (EMITP)

Introduction, administrative data, and referenced documents
Product information detailing functions, cabling, layout, grounding, and test settings
Test Site description - Test Chamber info
Test Equipment information (i.e. factors, settings, automation operation description/version, 'predicted' selection, calibration info)
Step-by-Step measurement procedures, block diagrams, computation explanation
Established test limits and approved DID format

DID EMI Test Report (EMITR):

Executive Summary, administrative info, and referenced documents
Product description, detailing functions, configuration, cabling, layout, grounding, modifications made (if any) and test settings
Tabular Test Data, Graphical Test Data, and Test Setup photographs
Test Engineer Log
Red-line Changes to document all EMITP differences
Approved EMITP-bonded as Appendix (if applicable)
Established test limits using approved DID format

Below is a short description of the aforementioned MIL EMC test standards in which MET Laboratories Military EMC Test Laboratory are accredited to perform:

MIL-STD-461 - This standard establishes interface and associated verification requirements for the control of the electromagnetic interference (EMI) emission and susceptibility characteristics of electronic, electrical, and electromechanical equipment and subsystems designed or procured for use by activities and agencies of the Department of Defense (DoD). Such equipment and subsystems may be used independently or as an integral part of other subsystems or systems. This standard is best suited for items that have the following features: electronic enclosures that are no larger than an equipment rack, electrical interconnections that are discrete wiring harnesses between enclosures, and electrical power input derived from prime power sources. This standard should not be directly applied to items such as modules located inside electronic enclosures or entire platforms. The principles in this standard may be useful as a basis for developing suitable requirements for those applications. Data item requirements are also included.

MIL-STD-704 – This standard establishes the requirements and characteristics of aircraft electric power provided at the input terminals of electric utilization equipment. MIL-HDBK-704-1 through-8 defines test methods and procedures for determining airborne utilization equipment compliance with the electric power characteristics requirements defined herein. Electromagnetic interference and voltage spikes are not covered by this standard.

MIL-STD-1275 - This standard covers the limits of steady state and transient voltage characteristics 28 VDC electrical power systems for military ground vehicles.

MIL-STD-1399 Section 300 – This requirement defines the standard interface requirements for and the constraints on the design for shipboard user equipment utilizing shipboard alternating current (ac) electrical power.

RTCA/DO-160 – This document defines a series of minimum standard environmental test condition (Categories) and applicable test procedures for commercial airborne equipment. The purpose of these tests is to provide a laboratory means of determining the performance characteristics of airborne equipment in environmental conditions representative of those which may be encountered in airborne operation.

MIL-STD-1399 Section 070 - Equipment installed on-board of a naval ship can expect to encounter magnetic field environments which would not be expected in other land base applications. The DC Magnetic Field environment is generated by the efforts of degaussing to counteract the normal magnetic signature of the metallic ship due to the ships consistent heading and normal electronic operation conditions. The DC Magnetic field can also be expected to be generated from individual sources such as electrical power cables, generators, motors, welding circuits, and electrical switchboards and control equipment. This magnetic environment may have a degrading effect of the performance of susceptible electronic equipment.

MIL-PRF-28800 - This specification covers the general requirements for test equipment used in testing and calibrating electrical and electronic equipment. The test equipment may be of commercial design and includes general purpose, special purpose, peculiar, console mounted, automatic test equipment (ATE), and calibration standards.

By the way: MIL-STD-461 emission test limits are 20 times more stringent than FCC limits, and as a result, can be difficult for manufactures to obtain MIL-STD compliance. If needed for EMC compliance, our Test Engineers, whom are skilled at debugging, can offer ‘real-time’ technical assistance to modifying your products electrical or mechanical interface to meet the stringent emission or susceptibility MIL-STD test limits.