Zigbee TXPOWER change issue.

Question

Hi, 
 
 I am trying to change the tx power of Zigbee using the following APIs : 
 1) zb_set_tx_power(0x32); 2) nrf_radio_txpower_set(NRF_RADIO_TXPOWER_NEG12DBM); 3) nrf_802154_tx_power_set(NRF_RADIO_TXPOWER_NEG12DBM); 
 
 None of this API makes a significant change in the TXPOWER CPU register and similarly I cannot see any change in the Wireshark RSS. Can you suggest a proper API to see the changes in TXPOWER.

Thanks

Edvin · Accepted Answer

Upon further inspection of the log, I see that the second message, which had RSS= -35 is coming from the coordinator, which I didn't change the TX power on. So the TX power is successfully changed. 
 
 Please see the following screenshot:

I am sorry, but my wireshark keeps crashing when I try to save a capture, so I can't save the sniffer trace. 
 
 Did you try to set it to -40? And when you claim it doesn't change, can you check the extended source, and verify that it is indeed from the device of which you changed the output power? 
 
 BR, 
 Edvin

Edvin · Answer

The RSS should start at the effect that you set, but naturally, the signal strength will drop when the packet is received, because of noise and effect loss both at the transmitting antenna, receiving antenna, and the distance between the devices. However, if you set the output power to -40, you should never see the RSS of -35, because it is not possible that the signal strength has increased over the air. Again, can you double check that the extended device address is actually the device that you changed the TX power on, and that it is not another node routing the message to the receiver? The extended network address is part of the packet. If you still claim that it is not changing, do you have a project where it doesn't work, and I can replicate it? Because I tried it in the light bulb example, and it worked there. 
 
 Best regards, 
 Edvin

Zigbee TXPOWER change issue.

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