I've tested the TX power of nRF52840DKs using CLI application and a sniffer (sniffer device is nRF52840 Dongle). Sent message from one DK to other one via UDP and observed the sniffer RSSI values with Wireshark.
The test platform was always kept same, meaning the distance between the sniffer and transmitting nRF52840 never changed (distance is about 10-15cm) and there were no objects between them. (I'm aware the RSI value sniffed isn't the output power of the device but the power of the signal that reached the sniffer)
Used CLI commands to send messages using:
ot udp send <I've put the IP addr of receiver here> 1234 HEYYY
and the resulting sniffer RSS value was -45dBm.
Then again using CLI and using command
ot diag powerI've seen that the power of my RX is currently 0dBm as shown in below image:
After enabling diagnostic mode and using command "ot diag power 24" the response was that I've set the tx power to 24dBm as shown below:
after doing configurations to send UDP message again, the RSI value of my new message became -25dBm. Any value until 24 reduced the signal strength and any value beyond value 24 didn't change it so I've assumed that the peak gain value is 24dBm. Now this is weird because product specification of nRF52840 says that the TX power is -20 to +8 dBm.
My questions are:
1- How can I set the TX power to 24dBm while the device limit is only 8dBm? Maybe I'm just setting it to 8dBm in the background and the response from CLI is just misleading?
2- How can I set my device's both TX and RX power with configurations in prj.conf and with functions in the main code, for Thread? (Seen some solutions but thought they are for Bluetooth)
3- If I'm using an RF FEM module with nRF52840, I'm guessing that the gain from FEM is always added to the gain set using commands in CLI, or does CLI tx power command also adjust the FEM gain?
Also, any recommendation of examples regarding adjusting and analyzing the Thread signals are appreciated.
