We have developed an own embedded device based on the Open-Q™ 410 SOM (Snapdragon 410 processor).
The operating system is a Yocto Linux with a kernel based on qcomlt-4.9.56.
During the first uses in the field, a lack of WIFI range was found.
Measurements in the test lab showed that the TX power of the wcn3620 was only 9 dBm (channel 1) and 8.5 dBm (channel 6) instead of the expected 18-20 dBm.
Corresponding power measurements confirm this. During an iperf3 test, the current changed by only 60 mA, way too less for 20 dBm.
We also found that changing the TX power (via iw dev wlan0 set txpower fixed xxxx) does not result in any change in the transmission behavior.
Although iw dev displays the changed value, it has no effect.
As a next test, we set up an access point on the unit and measured its signal strength. Here, too, tying to change the TX power has no effect and the transmission field strength is too low.
A further test with an access point on a DragonBoard with the current image (dragonboard-410c-sdcard-installer-sid-1125.img) shows an analogue behavior: No possibility to influence the transmission field strength.
We urgently depend on a correctly functioning WIFI.
What could be the cause of this faulty behavior?
Can we do any additional work ourselves?
Many thanks in advance for the help!