HDMI cable doesn't work

Hello,

I want to use a special HDMI connector with my Radar Zero.
Something like these: https://www.ebay.de/itm/353850495123?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&ssspo=anxvoeymqn-&sssrc=2349624&ssuid=XoCvucV_Qc2&var=&widget_ver=artemis&media=COPY

But they doesn’t work with my screen. Arent they compatible? Are there some special HDMI cables necessary to use the Radxa?

HDMI is a well defined standard and as long as the cable is comply to it they should work. For your issue you might want to check if the cable works on other devices to rule out bad cables.