How to set the RF output power of Stm32wl55?

[BISIK.18]

Hi, How can I set the RF output power of stm32wl55 in a LoRaWAN application?  

I have Nucleo board, but it seems transmission power is adjusted automatically.

The distance between the Gateway and Nucleo is a bit far, so I need to increase TX power.

If I read TXPower using functions of LmHandler APIs, I always see 0(I think this means 0dBm output power). How to set TX power? (I've tried SetTxPower function, but I still read 0)

[JoBackMonkey]

I am not sure if it meets your need, but I just saw a configuration for that in the CubeMX interface.

In the tab called "Tools", there is a left column containing "SubGhz Configuration", you can find the "Output Power" parameter there.

[BISIK.18]

Oh. Let me check it.

[BISIK.18]

There're 2 options: 10dBm and 14dBm. I always see zero(0) with params->TxPower in OnTxData callback.

[joe_lambord]

@BISIK.18​ Hello, I have the same problem with my two nucleo boards. What is the maximum distance in transmission that you managed to cover?

[BISIK.18]

I don't really know the answer. I am still trying to find the actual TX power value. I've got about 1km distance so far.

[Louis AUDOLY · Accepted solution]

Hello all,

As you said, the Tx Power is calculated automatically before each Tx.

Before you are joined to a network, the Tx parameters will be reset at their default value (to set the power at it's maximum for example).

Once you are joined, the parameters won't be reset, and you could set your desired power.

About the power 0 you are receiving, it's normal, the value you are receiving is just an index and not a dBm value. Moreover, the index is the opposite of the corresponding dBm value : 0 is the maximum power available, and depending of your region, 7 (in EU868) is the lowest power you can choose.

Table from the regional parameter EU868 you can find here !

With this index value you will calculate the corresponding power with this formula :

You can have more details about each regional parameters Tx power here ! (Table 4)

Sorry for the late reply but I hope this helps

Regards