How to set BLE tx power

RE: How to set BLE tx power

Hung Bui — Mon, 02 Oct 2023 07:58:00 GMT

Hi Timothy,
Please create a new ticket for your question.

RE: How to set BLE tx power

timl2415 — Tue, 26 Sep 2023 22:22:08 GMT

Hi Hung Bui,

I'm also interested in increasing the BLE tx power on my nRF52840 but I also have a nRF21540 FEM which is only rated to an absolute max of +5dBm. Does this option check for FEM presence downstream? I assume since the max is +8dBm the option only controls the output power from the nRF52840.

RE: How to set BLE tx power

Hung Bui — Tue, 19 Sep 2023 07:53:12 GMT

Hi Mariano,
Please create a new ticket if you have follow up question as it's a closed ticket.
The maximum value of CONFIG_BT_CTLR_TX_PWR_ANTENNA should be the maximum value of TX Power of the chip. You can find this in the specification of the chip. Here maximum TX Power of nRF52840 is +8dBm.

RE: How to set BLE tx power

Mariano — Mon, 18 Sep 2023 15:41:30 GMT

Hi, I'm testing this feature. What is the maximum value I can setup for CONFIG_BT_CTLR_TX_PWR_ANTENNA. I can't find any reference in the documentation

RE: How to set BLE tx power

Hung Bui — Mon, 15 May 2023 13:02:06 GMT

Hi Hendrik,

I assume the problem is solved ?
You should be able to clearly see the difference in the range when you do -8 and +8dBm. You can just use a phone to verify that.

RE: How to set BLE tx power

Hendrik — Mon, 15 May 2023 12:40:22 GMT

I tried changing it through Kconfig which edits zephyr/config and manually by putting it in my proj.conf. Neither seem to have any impact. When creating a new build configuration, should I select a particular option (system default vs proj.conf)?

Edit: it seems like my signal strength varies a lot but I do see a difference between -8 and +8 dBm

RE: How to set BLE tx power

Hung Bui — Mon, 15 May 2023 10:16:16 GMT

Hi Hendrik,

It should work. I did a quick test here with peripheral_lbs example and when I add

CONFIG_BT_CTLR_TX_PWR_ANTENNA=8

I can see on the phone (via NRF Connect app) that the RSSI increased quite a lot (-33dBm at 0dBm txpower and -22dBM at 8dBm txPower)

Also I can see the current consumption increased when I use 8dBm

Another thing you can try is to control the tx power dynamically. See here:

How to set TX power to maximum +8dbm for advertising as well as when connected