Most common causes
- Antenna is poorly matched or wrong frequency.
- Antenna is inside a bad enclosure or near metal.
- Gateway or node antenna is too low.
- Coax cable or connector loss is too high.
- Spreading factor, bandwidth or TX power settings are not suitable.
How to test
Start with antenna placement, cable loss, power supply noise and final enclosure testing. Then compare RSSI, SNR, packet loss or return loss before and after each change.
What to verify
Check antenna frequency, matching network, connector type, ground plane, cable routing, supply ripple and nearby sources of interference.