rf95.setFrequency(frequency);
// Setup Power,dBm
rf95.setTxPower(13);

// Setup Spreading Factor (6 ~ 12)
rf95.setSpreadingFactor(7);
  
// Setup BandWidth, option: 7800,10400,15600,20800,31250,41700,62500,125000,250000,500000
//Lower BandWidth for longer distance.
rf95.setSignalBandwidth(125000);
  
// Setup Coding Rate:5(4/5),6(4/6),7(4/7),8(4/8) 
rf95.setCodingRate4(5);