STM32WLE5CCU6 RF Range issue

[Shariq]

Hi,

We have a project in which we are using the STM32WLE5CCU6 and we are trying to communicate through its RF but we are getting range upto 200m while we are expecting range in few KM. we have tested our board with the nucleo-wl55jc1 default antenna. We have tried to communicate on 915MHz with 125KHz BW for different SF from 7 to 12 but getting same range.

we are using STM32WLE5CCU6 instead of STM32WL55CC. The reference design referred is (STM32WL QFN 4 Layers IPD - High Power Mode - Reference Board) .Does this makes any difference?

Can you suggest us how we can achieve expected range.

Thanks

[Andrew Neil]

What is at the other end of the link?

Just plain LoRa, or LoRaWAN?

Is this a custom board?

If so, you'll need to show your schematic and layout.

What code are you using?

What range do you achieve with the nucleo-wl55jc1 ?

[Shariq]

At both transmitter and receiver side we are using board implemented using STM32WLE5CCU6 having same specifications

Just plain LoRa

Yes, we are using custom board
version: STM32Cube_FW_WL_V1.3.0
Code developed with the help of example code: SubGHz_Phy_PingPong

With the nucleo-wl55jc1 we have achieved 200m.

[Andrew Neil]

Sorry, that schematic is too low-res to read any of the text.

Does your custom board have  a PA?

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@Shariq wrote:

With the nucleo-wl55jc1 we have achieved 200m.

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So your custom board is achieving the same range as the nucleo-wl55jc1

Is that with the Nucleo in its high- or low-power Tx mode?

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@Shariq wrote:

we are expecting range in few km.

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On what basis are you expecting that ?

[Shariq]

Sorry for the inconvenience, please find the schematic attached

No, we are using inbuilt PA of STM32WLE5CCU6 with gain set at 22dB.

Nucleo was used in high power Tx mode.

[Shariq]

Hi, 

On basis of power we are expecting range in KM

[STTwo-32]

Hello @Shariq 

First, I suggest you refer to the AN5407 for your design to have the best RF performance. You also may think about using an antenna with a better gain. Finally, try to maximize the Tx Power to have better range.

Best Regards.

STTwo-32