EMC test issues on A20-OLinuXino-MICRO

[ANi]

Hello,
We have a setup with A20 Micro, Mod IO2 and Mod RGB boards. A20 is connected to a Teltonika RUT240 mobile router. In the EMC radio emissions test the setup gave peaks in 225 MHz and 324 MHz above the requirements and plenty of other peaks just barely on the safe side.
I found this article for A20 Lime2 board: https://olimex.wordpress.com/2019/08/29/magic-shield-plates-helps-naked-a20-olinuxino-lime2-board-to-pass-ce-emc-requirements/
We tried similar Farady cage plates with no effect what so ever. Snap-on ferrite beads on the ethernet cable had some effect and beads added on almost every cable made the peaks just under the threshold. We didn't have the time for further investigations during that test day.
Any ideas what to do before next tests and what fixes to try during next session?
 

[LubOlimex]

Basically what was written in the blog post you shared is everything we've ever tried.  The metal cage was the only hardware fix that let the board pass certification alone. So my advice is to try with different metal box designs/

Yet that post was for LIME2 and you have MICRO, notice there are differences:

- MICRO has 100MbE while LIME2 has 1000MbE
- the routing is different, the location of the metal cage might need to be different.

Additionally, any long cables would act as antennas and might increase the noise. So try to measure the noise without MOD-RGB or MOD-IO2 attached and compare with them attached.