Default Transmitter Output Power

RE: Default Transmitter Output Power

jschorey — Tue, 11 Apr 2023 14:46:30 GMT

Understood. Thanks. I found this article handy, too, especially since we use Bluetooth 4 rather than 5.

blog.nordicsemi.com/.../things-you-should-know-about-bluetooth-range

RE: Default Transmitter Output Power

Hieu — Tue, 11 Apr 2023 14:33:17 GMT

There is an old blog post on that topic here: https://blog.nordicsemi.com/getconnected/tested-by-nordic-bluetooth-long-range.

I am pretty sure the number there is recorded with a very idealistic environment though. I am not sure if that's what you mean by open air.

In a city or office environment, you will have a lot of radio interferences and obstacle. The range will be a lot smaller. It varies a lot based on the actual environment, which is likely why we won't find a lot of people dare making any claim on ranges outside of the ideal case.

RE: Default Transmitter Output Power

jschorey — Tue, 11 Apr 2023 14:02:42 GMT

Hieu, I wonder if you could answer one other question... Do you know the approximate BLE open air transmit range at 0 dBm?

RE: Default Transmitter Output Power

jschorey — Tue, 11 Apr 2023 13:21:52 GMT

Thank you. That is very helpful.

RE: Default Transmitter Output Power

Hieu — Tue, 11 Apr 2023 13:20:52 GMT

Oh sorry, I didn't notice that part was also not clear.

The default for the SoC is 0 dBm.

In the nRF5 SDK, if you don't explicitly change it otherwise, it will be 0 dBm. I am not sure if the SoftDevice set it again to 0 dBm, or if it just leaves the TXPOWER register unchanged.

As you mention the SoftDevice, I don't think you are using the nRF Connect SDK (NCS). However, just in case, please note that with the NCS, there is another concept also using the term "default." It is the default configuration for the application software. For BLE, it is configurable by the Kconfig CONFIG_BT_CTLR_TX_PWR. I am not sure how it is done in other protocols. If you need to know about the default when using NCS with other wireless protocols, please let me know..

RE: Default Transmitter Output Power

jschorey — Tue, 11 Apr 2023 13:01:00 GMT

Thank you. I see "-20 to +4 dBm TX power, configurable in 4 dB steps" in the Key Features section. And I understand your point, "the typical value is given for the "Maximum output power" property, not the typical TX Power of the device." However, my question still remains: What is the default transmitter power setting if the user's App does not change it? It would appear to be 0 dBm. Would this be set in the softdevice?

RE: Default Transmitter Output Power

Hieu — Tue, 11 Apr 2023 10:27:21 GMT

Hi jschorey,

My apology for the long wait. It has been the Easter holiday, but we are now back to work.

I looked over a few SoCs which has the TX Power you listed, and my guess is that you are working with the nRF52832?

If so, in table 23.15.4 of the nRF52832 Product Specification v1.8, the typical value is given for the "Maximum output power" property, not the typical TX Power of the device.

Hieu