AT command to set Tx RF power level

[nbonniere]

For a short range point to point WiFi serial communication, it would be nice to be able to reduce the Tx power. It would also reduce power consumption on battery.

[beckdac]

Is this possible with the ESP libraries?

[nbonniere]

It seems to be possible to set the power from 0 to 20.5 according to some comments such as on:
esp8266/Arduino#764
and
https://github.com/esp8266/Arduino/blob/41074245a8d3029270622a8b489d53fdfedb2a22/libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp#L169-L179

/** * set the output power of WiFi

• @param dBm max: +20.5dBm min: 0dBm /
  void ESP8266WiFiGenericClass::setOutputPower(float dBm) {
  if(dBm > 20.5) {
  dBm = 20.5;
  } else if(dBm < 0) {
  dBm = 0;
  }
  uint8_t val = (dBm4.0f);
  system_phy_set_max_tpw(val);
  }

[nbonniere]

The datasheet for the AT command set also has power control support in 0.25 db steps, 0 to 20.5 : maximum value of RF TX power, range 0 ~ 82, unit:0.25dBm

https://www.itead.cc/wiki/images/5/53/Esp8266_at_instruction_set_en_v1.5.4_0.pdf