How to limit TXPower to 50mW?

End Devices (Nodes) LMIC
1

Will it be possible to set TX Power for RFM95 at 50mW?

Saw this in the sample code.
// Set data rate and transmit power for uplink (note: txpow seems to be ignored by the library)
LMIC_setDrTxpow(DR_SF9, 14);

Are there any other ways to do so?

Thank,

Somsak

2

Setting txpow in the band definitions (https://github.com/matthijskooijman/arduino-lmic/blob/master/src/lmic/lmic.c#L545 ) should work. Note that most bands already have a limit lower than 50mW/17dBm.

3

Thank you. If it is lower than 50mW, our node is built in compliance with our regulation. Is there not so expensive testing equipment for home use?

Somsak

4

Please, I have a doubt about this.

I’m using mode ABP with channels 9 to16 for US915_125kHz and when I print the value of txpow every time is 30. I guess that is because:

static void updateTx (ostime_t txbeg) {
u1_t chnl = LMIC.txChnl;
if( chnl < 64 ) {
LMIC.freq = US915_125kHz_UPFBASE + chnl*US915_125kHz_UPFSTEP;
LMIC.txpow = 30;
return;

This code is the cause?

I need to fix Txpower because I need to measure the rssi for to compare with simulations results.

Cheers,