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Electronics => Beginners => Topic started by: ocset on February 07, 2021, 03:13:42 pm

Title: Cheap Near field measurements for preparing product for radiated emissions test
Post by: ocset on February 07, 2021, 03:13:42 pm

Here is a good question for an EMC sub_forum  that could  if wished, be added to this website?

How do proper EN55032, far field radiated emissions scan plots correlate with  plots obtained cheaply with near field probes?

In other words, if we do a proper radiated emissions scan plot......and then we change a filter component, and the re-done  radiated scan comes out worse....would the  re-done near field plot also come out worse? (and vice versa)

Title: Re: Cheap Near field measurements for preparing product for radiated emissions test
Post by: TimNJ on February 07, 2021, 07:32:13 pm

We have a TekBox TBCP1-250 RF current probe. Put it on the AC input cord.

You can take a look at this:

https://www.tekbox.com/product/AN_-RF_current_to_electric_field_strength_extrapolation.pdf (https://www.tekbox.com/product/AN_-RF_current_to_electric_field_strength_extrapolation.pdf)

My recommendation is to run a real, preliminary scan at an accredited lab as a baseline. Then use your current probe measurements while you make changes to your circuit/system. Once the current probe measurement shows enough improvement, go back to a real lab and confirm.

Title: Re: Cheap Near field measurements for preparing product for radiated emissions test
Post by: Simon on February 08, 2021, 12:36:49 pm

https://www.eevblog.com/forum/renewable-energy/cheap-near-field-probe-and-emc-analyser-for-radiated-emissiaons-of-smps/msg3451738/#msg3451738 (https://www.eevblog.com/forum/renewable-energy/cheap-near-field-probe-and-emc-analyser-for-radiated-emissiaons-of-smps/msg3451738/#msg3451738)