Setting TX power using iw and getting random values back

Using an AW-CB375NF (RTL8822CE) 2x2 M.2 WiFi card and trying to understand the different TX levels (in preparation for sending an embedded device for compliance testing), I can't make sense of the disparity in values I am supposedly setting, what iw reads back and more importantly what the Realtek test tool reports back. What follows is the log of me setting the TX power using iw set txpower , reading it back again using iw info , then validating it using the Realtek test tool. All different! 0dBm: # iw dev wlan0 set txpower fixed 0 # iw wlan0 info Interface wlan0 ifindex 4 wdev 0x1 addr cc:47

Question by Hamza on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.