Just like many of you I am using the HopeRF RFM95W module with mcci-catena/arduino_LMIC.
My question to you: What is the lowest current consumption you have been able to achieve while transmitting with this module? I am trying for a low-range, low-power application, so I would like to lower the power basically as much as possible.
I have found that
LMIC_setDrTxpow() does not work, as reported by other open issues. Therefore, for testing purposes I hard-coded a value in lmic_us915.c : void LMICus915_updateTx(ostime_t txbeg)
// LMIC.txpow = 30; //old value LMIC.txpow = 0; //edited value
I believe this is one of the lowest sanctioned transmit power values, but to be honest I’m not sure.
Even after this change (which did lower the power somewhat), I have found that the actual measured full-system current consumption values during a transmit are much more than I would expect: Like 35mA = 115mW @3.3V. This is with the constant overhead of the microcontroller (15mA when on) already subtracted. I know there are system overhead costs and such, but this is significantly more than the stated 25/50mW and numbers like that I have seen thrown around.
Any thoughts on how to further lower these consumption numbers, as well as your personal experiences with the power consumption of the RFM95W + LMIC?