LoRaWAN Gateway Troubleshooting: RSSI, SNR & Packet Loss

When an IoT sensor stops reporting, panic sets in. Is the sensor dead? Is the battery empty? Or is the LoRaWAN gateway failing to hear it? This guide is a crash course in network diagnostics. We demystify the two most critical metrics on your gateway dashboard: RSSI (Signal Strength) and SNR (Signal Quality). We explain how to read these numbers to identify interference, cabling faults, and placement errors. By mastering these metrics, you can turn your LoRaWAN gateway from a black box into a precise diagnostic tool.

You deployed your sensors. You powered up your network. But the dashboard is showing gaps. Sensor #42 hasn't checked in for three days.

Before you send a technician on a four-hour drive to replace the sensor, look at the data. Your LoRaWAN gateway is constantly telling you exactly what is wrong; you just need to know how to listen.

Network troubleshooting comes down to three variables: RSSI, SNR, and Packet Loss.

These metrics are the pulse of your network. If you understand them, you can pinpoint whether a problem is caused by a concrete wall, a broken cable, or a noisy transformer near your LoRaWAN gateway. This guide explains how to diagnose the health of your infrastructure.

Every time a LoRaWAN gateway receives a packet, it tags it with metadata.

This is the "volume" of the signal.

• Measured in: dBm (decibel-milliwatts). It is always negative.
• The Scale: -30 dBm is screaming loud. -120 dBm is a whisper.
• The Diagnostic: If the LoRaWAN gateway reports -125 dBm, the sensor is too far away or blocked by an obstacle. If it reports -10 dBm, the sensor is too close, which can actually blind the gateway (saturation).

This is the "clarity" of the signal.

• Measured in: dB.
• The Scale: +10 dB is a crystal clear conversation. -20 dB is trying to hear a whisper at a rock concert.
• The Diagnostic: If RSSI is good (-80 dBm) but SNR is bad (-15 dB), your LoRaWAN gateway is suffering from interference. There is "noise" nearby drowning out the sensor.

Engineers coming from Wi-Fi or Cellular are often confused by LoRaWAN numbers. In Wi-Fi, an SNR of -5 dB is a dead link. In LoRaWAN, it is perfectly fine.

The demodulator inside an industrial LoRaWAN gateway is magic. It can decode signals that are weaker than the background noise.

• SF7 (Fast Speed): Needs an SNR of roughly -7.5 dB.
• SF12 (Slow Speed): Can survive an SNR of -20 dB.

Rule of Thumb: If your LoRaWAN gateway shows an RSSI better than -115 dBm and an SNR better than -10 dB, your link is healthy. If it drops below these, expect packet loss.

You receive 80% of packets, but 20% are missing randomly throughout the day.

• Cause:Collisions. Too many sensors are talking at once, or the LoRaWAN gateway is placed too close to another gateway causing interference.
• Fix: Add a second LoRaWAN gateway to share the load or adjust the sensors to transmit less frequently.

You lose connection every day between 2 PM and 4 PM.

• Cause:Interference. Is there a heavy machine (pump/motor) next to the LoRaWAN gateway that runs during those hours? Is a delivery truck parking in front of the antenna?
• Fix: Move the LoRaWAN gateway antenna away from noise sources.

A sensor that was working suddenly stops forever.

• Cause: Battery death or physical damage.
• Check: Look at the last packet the LoRaWAN gateway received. Was the RSSI trending down? (Drifting alignment). Was the battery voltage low?

Sometimes, the problem isn't the air; it's the hardware. If your LoRaWAN gateway reports low RSSI for every sensor (even close ones), you have a hardware issue.

1. Water in the Cable: If you used a cheap antenna cable without waterproofing tape, water has likely wicked inside. Water absorbs RF. Your LoRaWAN gateway is deaf.
2. The "Pigtail" Break: The tiny cable connecting the external N-connector to the internal circuit board is fragile. If you overtightened the antenna, you might have snapped this wire inside the LoRaWAN gateway.
3. Antenna Mismatch: Did you plug a 2.4 GHz (Wi-Fi) antenna into the 915 MHz (LoRa) port? They look the same, but the LoRaWAN gateway will not receive signals efficiently.

You cannot fix what you cannot measure. The logs inside your LoRaWAN gateway are the most powerful tool you possess.

By monitoring RSSI and SNR trends over time, you can move from "reacting to failures" to "predicting maintenance." You can spot a degrading cable or a growing tree before it kills the link. A well-monitored LoRaWAN gateway is the difference between a reliable network and a maintenance nightmare.