I am using XBEE PRO S2B module series.I am not able to get range 1.2 Km as mentioned in datasheet. I am getting only 160m with no data loss at line of sight. My instrument is Battery powered(3V,5000mAH). I have also tested it in boost mode at power level 4, still it failed to work. Can there be any environmental interference? Kindly suggest best possible way to improve range.