If you found this video useful, please check out my new "Practical EMC for IoT Designers" video course. This comprehensive course contains over 10 hours of video material that cover every aspect of EMC testing for intentional transmitters in accordance with Radio Equipment Directive (RED), ETSI, ITU-R, and EN standards. Apply "RF50" discount code for a 50% off during limited promotion this year only. Don't miss out! www.pcbforemc.com/courses
Sure! The main isssue was that the product has an HDMI interconnect cable and a 90degree RA HDMI plug. I noted that if I plug a display directly to the PC, even without a cover, then the emissions dissapear. That solution would be ideal, but it wasn't possible to actually do that. So the pass was achieved through a combination of: a) better quality HDMI cable, linked below, which removed the harmonics, and b) adding a ferrite clamp, which reduced the fundamental. These fixes are acceptable, because they can easily be implemented in production without a major change in design. A metalwork re-design would require a re-test on the other hand. kabeldirekt-store.de/en/products/hdmi-2-0-kabel-top-series-4k-8k-blau
@@DrEMC-sf8rx Hi Dr. Emc, can you share some knowledge why ferrite clamps work on shielded cable? Besides, why does it only reduces the fundamental frequency 148.5Mhz but not the higher harmonics?
@@TheZoro-ub1zm great question! As you've implied, the problem is that shielded cables are not so shielded after all. Magnetic fields penetrate metals with attenuation and create electric fields that propagate further. So, a thin sheet of metal won't stop strong magnetic fields even if it's reflective for electric fields! Of course, commerical cables are relatively thin, and this is why EM fields exist around them, which are the strongest at their fundamental frequency. ps. You can also watch my other video about EM shielding: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4TaFm_Y_E2c.html
Hello Dr. EMC. I have just subscribed your channel. I came to learn in RU-vid and I saw this video that was so interesting !! because I am an EMC engineer in the railway project. My role just evaluated or approved the electrical devices which were installed in the railway system for mitigating the EMI risks for assuring the whole system. Based on my experiences, I just knew a bit knowledge from theories or textbooks. It was that meant I never saw this kinds of actual EMC tests according to EN 50121-4 before until I met the channel. Not everybody could have a chance or spend times in the accredited labs like you to familiarize with the EMC apparatus. I appreciate you to create the contents like this more. Thank you. ❤
