Sensing distance when doing EMC 61000-4-6 test

[simbaliya]

Hello, guys. I have a concern on IEC 61000-4-6, in the standard is never mentioned when you do the test, how do you position the detecting object and optical sensor. I have heard several methods.

1. Try 1/3 and 3 times of maximum sensing distance see if there's wrong switching;
2. Try critical detecting and non-detecting sensing distance.
3. Try put object in sensing range and then remove object.

I am now confused which way is correct, please help.

 

[simbaliya]

Anyone can help?

 

[D.A.(Tony)Stewart]

I once did these tests long ago in a shielded room, which had big standing waves for notch at 1/4 wave null around 60MHz so readings must be checked carefully to,avoid over driving amplifier with Field strength meter via optical,cable . two E field meters is better.

Those methods are to prevent false E fields from reflections. so E field meter should be equidistant from source and walls and not too close to D.U.T. 1/2m -1m away

distance does not matter if you measure with E field meter. we use a variety of antenna incl bi-conical dodecahedral