RAK3172 continuous wave test

LPWAN Modules / EVBs RAK3172
#1

I am writing firmware for compliance testing using the AT+CW (send continuous wave) command. The maximum transmission power for this command is +22dBm, yet the maximum transmission power for the module is +30dBm in several bands (e.g. US915, txpower=0).

How can I appropriately demonstrate full compliance when +30dBm is not achievable in test mode?

Many thanks

Stefan

#2

Hi @stefan_bare ,

I am not really an expert in compliance but probably you can share some detail so I can ask expert in our team regarding this matter. Some insights/questions I have.

  1. What compliance test are you doing? The modules has +22dBm output which is far from FCC limit AFAR Communications Inc. - Outdoor Wireless Networks - www.afar.net.
  2. If you are doing LoRaWAN compliance, the stm32wl dev board was LoRa Alliance certified and +30dBm test is not performed as I look on this document https://lora-alliance.org/wp-content/uploads/2021/01/65979RLR.003-US.pdf.
#3

Thanks for the advice, @carlrowan.

In answer to your questions:

  1. Tests are EU and US radiated emissions testing. Is the +22dBm output limit shown in the datasheet anywhere? Also, does output power vary with supply voltage?
  2. Thank you for this link, very useful.
#4

Hi @stefan_bare ,

The chip inside RAK3172 is based on STM32WL SoC. You can find more details (and the +22dBm specs) here.