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beegee-tokyo / SX126x-Arduino

Arduino library to use Semtech SX126x LoRa chips and modules to communicate
MIT License
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Set TX Power to high values. #101

Closed gamma2 closed 1 year ago

gamma2 commented 1 year ago

Good morning, I'm doing some tests with my heltec wifi lora32 v3. How can I set the transmission power to max values (20/22) db? I try to set it with the following statement static lmh_param_t lora_param_init = {LORAWAN_ADR_OFF, DR_0, LORAWAN_PUBLIC_NETWORK, JOINREQ_NBTRIALS, 22, LORAWAN_DUTYCYCLE_OFF}; but it seems to have no effect. Maybe it's not within the spec of EU868 and if so, how can I force it?

beegee-tokyo commented 1 year ago

Hi gamma2,

Two things.

1) The LoRaWAN stack doesn't set the TX power in dBm, it uses the values 0 to 10 with 0 being the highest TX power. 2) The LoRaWAN stack does translate the values of 0 to 10 to the allowed TX power per region.

So a) for the highest TX power, the value in the lmh_paramt structure is 0 b) you cannot set a TX power of 22dBm when using EU868. It is limited to 16dBm_.

Reference TX power per region which is extracted from the regional LoRaWAN parameters issued by the LoRa Alliance.

gamma2 commented 1 year ago

Thanks for the clarification.