how to get txPower to calculate distance from RSSI

[sandeepmhptr]

QBluetoothServiceDiscoveryAgent serviceInfo; quint i =serviceInfo.device().rssi();

here i = -43

how to convert it to distance? I got the link Understanding ibeacon distancing but how to get the transmitter power? to calculate the distance according to formula?
int ratio_db = txCalibratedPower - rssi;
int ratio_linear = Math.pow(10, ratio_db / 10);

int distance = Math.sqrt(ratio_linear);

[patrik08]

Test it... as javascript ... :-)

http://www.metageek.com/training/resources/understanding-rssi.html

function calculateDistance(rssi) {
  
  var txPower = -59 //hard coded power value. Usually ranges between -59 to -65
  
  if (rssi == 0) {
    return -1.0; 
  }

  var ratio = rssi*1.0/txPower;
  if (ratio < 1.0) {
    return Math.pow(ratio,10);
  }
  else {
    var distance =  (0.89976)*Math.pow(ratio,7.7095) + 0.111;    
    return distance;
  }
}