A day at the 10 Meter Anechoic Chamber

People are always asking what I do for living so here is a review of what I am up to today. The chamber I'm at today looks like the picture on the right.


I am at an EMI/EMC test facility. EMI means Electromagnetic Interference and EMC means Electromagnetic Compatibility.  EMI testing measures the electromagnetic emissions from a device. These are the electrical signals emitted, we use an antenna and a spectrum analyzer to measure the frequencies and then compare the amplitude to the limits set by the various regulatory agencies around the world. Today we are testing to CISPR 11.




After seeing what the EUT (Equipment Under Test) emits, we do EMC testing, where we bombard the device with various radio-frequencies to see if that causes any errors.

Most chambers look like what people call a sound proof room. The principle is the same, the capture and reduction of waves; sound waves, radio waves, light waves, X-rays, AM, FM,  etc all different wavelengths of energy.

A quiet day at the lab is a good day. That means nothing failed and the device is good. A bad day at the lab can be very interesting and frustrating. If the device is emitting too much noise we have to find out what is making the noise and figure out how to quiet it. We add grounding and shielding to try and get the emissions down.

If the device fails when bombarded with energy, we add ferrites and other materials to try and harden the device.  You see these as the bumps near the ends of cords.

I work with Electrical Engineers and Mechanical Engineers to make sure that the device is safe when released into the market. Everything I know about grounding, shielding, wavelengths and electrical design I learned on the job.