LoRaWAN Range Testing and Coverage Planning

Why Range Testing Matters

Gateway placement makes or breaks LoRaWAN deployments. Too few gateways means devices can't connect. Too many wastes money. Range testing before full deployment saves time and budget.

What Affects Range

Environment:

• Urban: 2-5km typical (buildings block signals)
• Suburban: 5-10km (less obstruction)
• Rural: 10-20km possible (line-of-sight helps massively)
• Indoor: 100-500m (concrete/metal attenuate heavily)

Gateway antenna height: Every meter of elevation helps. Gateway on ground floor vs rooftop makes 2-3x difference in coverage. Fresnel zone clearance matters - first 60% of line-of-sight path should be clear of obstacles.

Transmit power: Devices typically use 14dBm (25mW). Some support 20dBm (100mW) but drains battery faster. Most deployments stick with 14dBm.

Spreading factor:

• SF7: Fast (5-10 kbps), short range, low battery use
• SF12: Slow (250 bps), long range, high battery use
• ADR (Adaptive Data Rate) automatically selects optimal SF

Antenna gain: Gateway: 3dBi omnidirectional standard. 6-8dBi improves range 30-50%. Directional 12-15dBi for specific coverage sectors.

Device: PCB antenna typical (0-2dBi). External whip antenna (3-5dBi) adds ~500m-1km range.

Range Testing Method

Equipment needed:

• Test device transmitting every 30-60 seconds
• GPS tracker or phone for location logging
• Network server showing packet reception
• Vehicle or walking route

Test procedure:

1. Install gateway at proposed location
2. Drive/walk outward from gateway in multiple directions
3. Log GPS coordinates where packets stop being received
4. Mark boundaries on map
5. Identify dead zones and weak coverage areas

Metrics that matter:

• RSSI (Received Signal Strength): -120 dBm is limit, -100 dBm is good
• SNR (Signal to Noise Ratio): Negative SNR still works with SF12, positive SNR preferred
• Packet loss: <5% acceptable, >20% means coverage problems

Interpreting Results

Strong signal (RSSI > -100 dBm, SNR > 5 dB): Excellent coverage. Device will use SF7 (low airtime, long battery life).

Moderate signal (RSSI -100 to -120 dBm, SNR 0 to 5 dB): Acceptable coverage. Device uses SF9-SF11. Battery life reduced but reliable communication.

Weak signal (RSSI < -120 dBm, SNR < 0 dB): Edge of coverage. Device stuck on SF12 (slow, high battery drain). Packet loss likely. Need additional gateway or relocate existing.

Coverage Planning Best Practices

Gateway height priority: 10m gateway on ground beats 3m gateway with high-gain antenna. Get height first, then worry about antenna gain.

Overlap is good: Multiple gateways hearing same device provides redundancy. Aim for 20-30% overlap between gateway coverage areas.

Test at device height: Don't test holding device at head height (1.8m) if actual deployment is ground-level soil sensors (0.3m). Height difference affects results.

Time of day matters: Atmospheric conditions change. Test during typical operating hours. Temperature inversions at night can extend range unexpectedly.

Building materials: Concrete/brick: 10-15 dB attenuation per wall. Metal: 20-30 dB. Wood: 5-8 dB. Glass: 2-3 dB. Plan accordingly for indoor coverage.

Common Mistakes

Assuming theoretical range: Marketing claims "15km range" are line-of-sight, no obstacles, perfect conditions. Real world is messier.

Testing with only SF7: Device at network edge uses SF12. If you only test SF7, you miss weak coverage areas where device will struggle.

Single test pass: One drive-by doesn't show full picture. Radio propagation varies with weather, foliage (summer vs winter), time of day.

Ignoring gateway capacity: One gateway handles thousands of devices - in theory. In practice, 500-1000 active devices per gateway before congestion issues appear.

Tools for Coverage Modeling

RF propagation software: Radio Mobile, CloudRF - predict coverage based on terrain data. Useful for desktop planning before physical installation.

TTN Mapper: Crowdsourced coverage maps. Shows real-world range data from community. Good for seeing coverage in your area.

Field strength meters: Expensive (1000+ EUR) but accurate. Alternative: cheap LoRa test devices (50 EUR) work fine for relative measurements.

What I Help With

Services:

• Coverage planning and gateway placement recommendations
• Range testing methodology and equipment selection
• RSSI/SNR data interpretation
• Coverage gap identification and solution design
• Multi-gateway network optimization

You own everything:

• Coverage test data and analysis
• Gateway placement documentation
• Network design recommendations
• No ongoing fees after consultation