How to increase BLE TX POWER on nrf5340 in SDK v2.5.3?

RE: How to increase BLE TX POWER on nrf5340 in SDK v2.5.3?

Menon — Tue, 27 Aug 2024 11:48:05 GMT

Hello,

[quote user="GerardB"]set_tx_power(BT_HCI_VS_LL_HANDLE_TYPE_ADV, 0, 8);[/quote]

From the shared code snippet, I can see that you are trying to set a Tx power of +8 dBm for the nRF5340, which is not supported. The transmission power range for the nRF5340 is from -40 dBm to +3 dBm, as specified in the product documentation. For higher Tx power, you may need to consider using FEMs (Front-End Modules).

Please refer to this old Devzone thread where my colleague shares a sample for setting the Tx power in advertising mode. Note that this sample is only applicable to the nRF52 series (setting +8dbm) and is provided as a reference for implementation.

Kind regards,

Abhijith

RE: How to increase BLE TX POWER on nrf5340 in SDK v2.5.3?

GerardB — Fri, 23 Aug 2024 05:25:25 GMT

Thanks for your fast response Menon.

I was aware of the HCI_power_control example but from what I see there, it only changes the TX POWER for a particular BLE connection (so first a central needs to connect to the peripheral & then the peripheral can change its TX POWER level).

Our nrf5340 based board is configured as a peripheral. What we need is to ALWAYS improve the BLE signal strength - especially during advertising (when there is NO BLE connection yet). So it needs to be done after BLE is initialized, just before advertising starts.

I looked at the old Devzone thread you referenced & tried the code BUT although it builds OK, I do not see any difference in BLE signal strength when I run

------

set_tx_power(BT_HCI_VS_LL_HANDLE_TYPE_ADV, 0, 8);

just before

err = bt_le_adv_start(BT_LE_ADV_CONN_1ST30SECS, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));

------

Are you sure that "set_tx_power(..) will work on the nrf5340? Some of the other (old) threads I have seen on devzone seem to indicate that this will NOT work on the nrf5340. Can you confirm that it should work?

Thanks!

Gerard

RE: How to increase BLE TX POWER on nrf5340 in SDK v2.5.3?

Menon — Thu, 22 Aug 2024 12:14:02 GMT

Hello,

Please take a look at the HCI_power_control sample from the SDK. This sample demonstrates peripheral advertising with varying Tx power, which I hope will be helpful for your use case. You can find it here.

I’m also attaching an old Devzone thread that discusses an issue with a similar implementation. This may serve as a useful reference for your project.

Kind regards,
Abhijith