I also have issues with very bad range. I have 100-150 meters maximum, often with BAD_CRC.
As node i use an sx1276 and esp8266 powered with 2 penlites.
My gateway is the DIY mCard and RPi version.
I think it has to do with the antenna on the node i use, is there a special way this thing needs to be connected ? Also, maybe the voltage from the two penlites is too low. Any suggestions ?